The main thing you want to do when buying a used car is to take it to a 3rd party auto shop for a pre-purchase inspection, then use that information to renegotiate the price same as you would renegotiate a property during the option period as your due diligence develops.

But sit down with her and renegotiate some kind of agreement in the mean time whether it be month to month so you have a lease in writing.

He was kind enough to renegotiate with us realizing the predicament it would cause for us but we were only a fraction of the neighborhood.  

We had the inspection done and we may need to renegotiate the contract based on the inspectors findings(roof & HVAC repairs/replacement).  

I have closed 4 in the last 2 months...none were listed when I found them...and i kept it that way.The only person that will request a listing agreement is the call screener...and if you give them the wrong answer...you might as well hang up, call back and get another screener on the phone...and that goes for any question they ask you.Nobody can force the seller to list the property...and furthermore why complicate the situation...bring in a realtor and you can't change your offer at will...you have to fill out new paperwork signed by the seller to re-negotiate...extensions have to be signed...nightmare.You won't even get to a loss mitigator if you don't get past the call screener first...the negotiator won't be asking you questions like "is it listed?"

Say you make the offer for 200k but after due diligence, it needs to be 180k, can you renegotiate?

With all due respect, I disagree that any renegotiated contract is a novation.

If that inspection can get you out of the contract, then you're just as likely to walk / renegotiate, as the other is risky in the financing.FINALLY, and probably the most insightful for you.

Make sure you put an Inspection contingency into the contract as you will be able to evaluate the property with a professional while it is in escrow, and potentially re-negotiate if the figures do not work out as you had planned.

We had the lawyer send out a letter stating that the rents were obviously lower and we asked estoppel letters and for a credit for the rent difference for the duration of the 12 month lease (rather than renegotiate purchase price).