This is the essence of the prozbul: I submit to you, so-and-so and so-and-so the judges who are in such and such a place, that every debt due me I will [be allowed to] collect whenever I wish. And the judges sign at the bottom [of the document] or the witnesses.

A prozbul is not canceled. This was one of the things which Hillel the Elder instituted. When he saw that the people refrained from lending money to each other and transgressed what is written in the Torah (Deut. 15:9): Take heed lest there be an evil thought in your heart . . ., Hillel instituted the prozbul.