Before The Search This Prayer Is Said:

Blessed are you, Lord our God, king of the universe, Who has sanctified us with His commandments and has commanded us concerning the removal of hametz.

After The Search This Prayer Is Said:

Any hametz or leaven that is in my possession which I have not seen, have not removed and do not know about, should be annulled and become ownerless, like dust of the Earth.

The Following Morning After The Hametz Is Burned This Prayer Is Said:

Any hametz or leaven that is in my possession, whether I have recognized it or not, whether I have seen it or not, should be annulled and become ownerless, like the dust of the Earth.

These prayers take the form of a legal declaration and in the Hebrew prayer book appear to be written in Aramaic.(1)

Miscellaneous:

What is Nullification
Learn more about the Holiday Of Passover
Read about another Prayer
Read about our Messiah

Acknowledgments:

1). The Complete ArtScroll Siddur published by Mesorah Publications, ltd p.655