What if you don't intend to reissue them?

I'm in a scenario where checks have been lost; however, the original vendor wrote them off in their year-end financials and does not want a reissued check (essentially, forgiving the debt).  So, I need to "clear" or "cancel" the original checks and their corresponding expenses in my current accounting period without affecting the previous accounting period (in which the original transactions took place).

How does that get done?