Flip property purchase but deal never went through apparently

[Jordan Manning]

Hi all, i have a unique situation. Fix and flip deal. We bought a property from a seller who later found out his bank couldn't release his property from the portfolio without a big payoff. Long story short, he tries to pay us off but we already started demo, etc....In the end we came to a deal to help his situation with giving him 10k on the backend of sale. I am looking for advice or any template I can use to create this agreement of us agreeing to pay him the 10k once property is sold. thanks