Q. f you will not be at home during Pesach, and you do an early bedika, (see prior question) when and how do you do the Bitul Chametz?

A. After finishing the search he should recite the declaration of Bitul Chametz or nullification of chametz using the following text:
כל חמירא וחמיעא דאיכא בביתא הדין, דלא חזיתיה ודלא בערתיה לבטיל ולהוי הפקר כעפרא דארעא

meaning, “All chametz or leaven in this house (Bebeita Hadein) that I have not seen, and have not destroyed, shall be nullified and become ownerless, like the dust of the earth. (Sha’ar Hatzion 436: 5) The reason is that he is only annulling the chametz he is not going to use anymore in his home, and he will repeat the declaration next night after searching the room in the hotel. He should place the chometz found in a separate secure place.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a