Bedikas & Mechiras Chametz when traveling from home
Note 1: When planning to Sell ones Chametz
[In all the cases below that one is obligated to check his home before leaving, this does not apply if he will be selling his home to a gentile on the 14th. It is thus advisable to do so. However if by doing so he will have no other place to check before Pesach, then there is room to say that he should check at least one room, rather than sell it all.
Note 2: When traveling to a home within the same city:
The below cases are all discussing that one is traveling to a different city. However if one is moving elsewhere within the same city, then he does not need to search it before he leaves, but rather on the night of the 14th. Although he must search even rooms required to be only Rabinically checked.
Does one who is leaving within 30 days before Pesach and does not plan to return until after Pesach, or does not plan to return at all, have to search before leaving?
Do bedikah the night before departure unless appoints a messenger:
One who leaves his house before Pesach [to another city] and does not plan to return until after Pesach, or does not plan to ever return, then if he is not leaving anyone in his home which is able to do the bedikah on the night of the 14th, then if he is leaving within thirty days before Pesach, then he must check with a candle all of his rooms the night before he leaves and do a nullification [after the bedikah] the night before, with all the laws necessary but without a Bracha. This applies even if he never plans on coming back.
Exceptions: [However] if he appoints a messenger to do it for him on the night of the 14th, [then he does not need to check the house before he leaves]. [Similar if he is moving within the same city, then he does not need to check before he leaves, and rather checks on the night of the 14th, as will be explained below. Similarly if he plans to sell the house to a gentile, he does not need to check it before he leaves]
[The reason for why one becomes obligated within thirty days before is because thirty days before Pesach] one begins to ask and expound about the laws of Pesach, he therefore has the obligation to be careful and fulfill all the Rabbinical commands. [Meaning even though checking for Chametz on the night of the 14th when one nullifies it is only a Rabbinical obligation, nevertheless it takes effect thirty days before Pesach.]
Saying a blessing: One does not say the blessing of “Al biur Chametz” as he does when checking on the night of the 14th.
The reason for why no blessing is said is because the search which is being done now is not the main time for the search to be done as was instituted by the sages. As they instituted it to be done on the night of the 14th, and from there and onwards [if one did not check on the night of the 14th] until the end of the festival. [Meaning since the main institution of the sages was to check on the last opportunity possible which is the night prior to the festival which is the 14th, thus although this also obligates one to search beforehand if he will not be able to do so on the last night, nevertheless he may not say a blessing, as this was not the main obligation. Similarly we find this ruling in 433/7 regarding one who wants to check his house completely before the 14th, that no blessing is said].
If one forgot to check the night before: Then one checks it the next day using candle light [in those places where sunlight may not be used, as explained in 433]
Nullifying the Chametz after the bedikah: Immediately after the search one nullifies all his unknown Chametz which he did not find during his search, in order to fulfill the institution of the sages which instituted to nullify the Chametz immediately after the search, for the reasons explained in 434.
Removing all the known Chametz from ones home before one leaves: The moment before one leaves to travel he is obligated to remove all the Chametz [which he found by his search and which he placed aside for eating] from his property that is in this city that he is leaving from.
If a person has traveled to a different time zone for Pesach, where should he sell his Chametz?
Example 1: If an Israeli traveled to America for Pesach does he sell his Chametz in Israel or in America?
Example 2: If an American traveled to Israel for Pesach does he sell his Chametz in Israel or in America?
One who owns Chametz in the area which he traveled from is to always do the sale in whichever area is the earlier time zone [east versus west] whether he traveled to an earlier time zone or later time zone. Thus in both examples above, if one has Chametz in his home area he is to sell his Chametz through a Rav in Israel. [Although when doing so in the first example one should specify that he is only selling him the Chametz in that time zone, otherwise he will not be able to eat Chametz even before the 5th hour, as it was already sold.]
A further example-Flying from east coast to west in America: Thus when even flying for Pesach from the east coast to the west coast in America, or from the east coast to the middle of America, one needs to make sure to sell his Chametz in accordance to the time that Chametz becomes prohibited in the east coast. Similarly when flying to Hawaii from America for Pesach one must be careful to sell his Chametz by the Rav in area which he currently lives.
Flying from west to east in America: He must sell the Chametz in accordance to the time of the east coast.
Regarding buying back the Chametz after Pesach there is no problem for the Chametz to be bought back in a place that Pesach ends earlier then the time it ends in the place that one lives, as one has no intention to buy back the Chametz until after Pesach ends for him. However some Poskim rule that one is to sell the Chametz in the earlier time zone and tell the Rav to not buy it back on his behalf from the gentile until Pesach ends in his later time zone.
 436/22 However when leaving within the same the same city then he must check on the night of the 14th, like all other places.
 see Q&A regarding when the 30 days begin
 Although what is still a question is that since the burning of Chametz is a Biblical command, so why a blessing should not be said when destroying it, irrelevant to whether there was a Rabbinical command to search for it? A. Perhaps by a mitzvah of Shev Veal Taaseh we do not say a blessing for it. Furthermore perhaps since the Mitzvah will only be fulfilled latter on by midday even according to perspective of Shev vela Taaseh, therefore no blessing is said. Vetzaruch Iyun However according to Admur in 446/1 which learns the mitzvah is a kum veaseh, which works retroactively, and thus retroactively one has fulfilled a mitzvah, one can say that perhaps a blessing can only be said by a kum veaseh when the mitzvah is being fulfilled then, however when it is only retroactively fulfilled then no blessing is said. Vetzruch Iyun. Alternatively we can use the same logic as Admur uses in 446/1 regarding Chametz burnt after the 6th hour that no blessing is said, being that perhaps the mitzvah of Tashbisu is only a preparation for Baal Yiraeh and thus does not deserve a blessing ever before the night of Pesach. And thus the blessing of “Al Biur” which is said by bedikah is going on the Rabbinical mitzvah of bedikah.
 So rules Magen Avraham and is implied from the Tur and Shulchan Aruch and Rama. However the Chok Yaakov argues. [Kutrus Acharon 2]
 Igros Moshe 4/94; Minchas Yitzchak 7/25; Piskeiy Teshuvos 443; leaning opinion of Rebbe in Shulchan Menachem 3/229 being that we follow the area of the Chametz
This matter is subject to the following dispute:
First Opinion: There are opinions [Oneg Yom Tov; Kaf Hachaim 443/17; opinion of Rebbe ibid] which rule that one goes after the area that the Chametz is in whether to be stringent or to be lenient. Thus if one travels from Israel to America he must sell it before the 6th hour of Erev Pesach enters in Israel.
Other Opinions: Others [Many Shutim. See Piskeiy Teshuvah] however hold that one goes after the time zone of the area that he is in. Thus if one traveled from Israel to America then one can sell it before the 6th hour enters in his area America, and does not have to precede it to the time in Israel.
The Final Ruling: Practically we rule like this latter opinion, although it’s proper to be stringent like the former opinion to get rid of the Chametz prior to the 6th hour in the area that the Chametz is in. [So rules Igros Moshe 4/94. Minchas Yitzchak 7/25 brought in Piskeiy]
 Accordingly when one has traveled to a later time zone [east to west] one would need to make 2 sale contracts, writing in each one that it is only valid for the Chametz of its area, in order so he be able to still eat Chametz in the west after the time of the East has arrived.
 Pashut. Brought in Blumenkrantz
 Piskeiy Teshuvah
 Igros Moshe 4/94
 Rather the Rav is to buy it for himself and then the original owner will buy it back from the Rav.