Insurance claim on stolen ac units to cover mortgage payoff

[Natalie Allen]

I have a duplex under contract & during our inspection period we found replacing the two ac units would be much more expensive than expected.  The sellers offered to submit an insurance claim for the stolen ac units and take that $ to cover the difference between our new price & her mortgage payoff.  Has anyone successfully accomplished this?  If so, what should I do as far as an addendum or extension to the contract?  Is there anything I need/should do to make this happen?