A letter, generally sent by a lawyer, warning a borrower who is behind in payments on a loan that unless the loan is made current within a certain period of time, the lender will consider the borrower to be in default on the loan
Demand letters can be sent for debts owed, NSF cheques and stopped payment on a cheque. It may be used to maintain some goodwill between parties while encouraging payment, in order to avoid expensive litigation.
If needed, a "Fill Form" Demand Letter can be purchased in most office supply stores, to be legally executed, and serve notice to any party that you are trying to resolve a dispute.