Immediately after Havdalah on Motzaei Pesach, the rabbi asks the non-Jew if he would agree to sell the chametz back. If the non-Jew agrees, the deposit is returned to him and the loan becomes void. It is just like when you return the air conditioner to the store where you purchased it with a minimum payment on your credit card.
Since the terms of the sale are complicated, it is our practice to leave the transaction in the professional hands of the rabbi by signing a power of attorney in his favor, just as one would authorize an attorney to sell one’s house. The power of attorney sets forth the basic details of the type, value and whereabouts of the chametz and how it can be accessed during Pesach and the rabbi then sells the chametz and the location in the house where the chametz resides to the non-Jew on your behalf.
According to Rabbi Moshe Feinstein, if you cannot get to the rabbi to sign, you can empower him over the phone. Based on the principle of “zachin le’adam shelo befanav,” (one Jew may perform a mitzvah for another Jew even without his consent), many poskim rule that power of attorney can cover all members of the community, even those who forgot to sign the power of attorney or call the rabbi before Pesach.
If you are traveling to Israel for Pesach and you did not sell your chametz before you left the U.S., you should sell it in Israel before the fifth hour, Israel time, even though it is long before Pesach in the U.S. On Motzaei Pesach, however, you should wait until Pesach is over in the U.S. before buying it back.
Raphael Grunfeld’s book, “Ner Eyal on Seder Moed” (distributed by Mesorah) is available at OU.org and your local Jewish bookstore. Comments to the writer are welcome at Rafegrun@aol.com.