Short sale process

How to do this SS
Mortgage owned 175k
FMV 150k

Lets just say the bank approved the short sale for 75k. Would I have to show the bank a pre approved letter that I can purchase the home? How would I flip it to another investor since banks dont let you assign contracts? I am only wholesaling not rehabbing. Pls explain how this process will go.

another question

Let say I found someone in pre-foreclosure that owes 60k but is behind 8k in payments and taxes, and they told me that they want to stay in there home. What would I do since I am trying to flip the property to another investor for a fee. How would i be able to help them since i want to buy house?