Legal Question in Real Estate Law in California

Are you asking how to obtain one from a paid-off lender, or where to locate a legal form? If the former, ask the lender. If the latter, first note that while deeds of trust (per se) are reconveyed when paid off, we usually speak of "termination" of an assignment of rents rather than a reconveyance. I looked on line and there seem to be several readily-accessible on-line sources for boilerplate language for "termination of assignment of rents".