Hi Anthony,
Good job on getting some momentum, that’s key!
Okay so the first thing is don't look at appraisals... they are only good for bank financing and camp fires... Look at sold comps (last six months/within half a mile), which means you have to get access to the MLS, or know someone who has access and will get you information... I'm a wholesaler and have access through a Realtor friend, all you have to do is ask and let them know that you will only use it to pull comps-They may or may not do it… I digress...
You can tell the buyer no, it’s a cash deal and hold out for another investor, assuming it’s a good deal.
You can rent to own from the seller, and collect the down payment from your buyer, and work it out so that the owner gets so much a month from you, you get the difference from your buyer, and when the buyer is able cashes you out and you pay off the $40k. You would of course set a higher purchase price to collect the difference (Just FYI-I am least knowledgeable on this type of transaction)
You can do a subject 2 and take over the deed. You will then let the current owner know that they will get cashed out if this new buyer performs on a lease option (assuming that is what you did) or you can collect the deposit put the renter or L/O tenant in and sell the property as Turn Key- Then just adjust the price to what it would sell for quickly in your market...
There are all kinds of ways to make money, and this post could be a lot longer, but you will need to stick with your skill set and read up on what you don't understand to become well versed and able to handle situations like this... Best of luck!