Payment plan post lease end date

[Jim Klapmust]

My tenant was shaky on rent leading up to the coronavirus, and the subsequent shut down made the situation worse.  He's been my tenant for 5 years with good payment history, so I'm willing to work with him, and in earnest he asked about a payment plan to catch me back up that extends beyond the lease end date (June 30th).  He is moving out when the lease ends.

What contract/agreement should I use to setup a payment plan that starts now but extends beyond the lease end date?  I've read much about payment plans, but they all seem to be within the context of a ongoing lease.

TIA for your help!