Delayed financing exception

[David Woolfork]

Please help this BP newbie out. I've been reading posts on the "Delayed Financing Exception" by Fannie Mae.  Lets say that you pay 70k all cash for a house and the house is appraised at 100k. As I understand it you get to pull back out your 70k plus the closing costs? Do you get to pull out more if you do some rehab and it appraises at say 120k? This sounds great from what i've read just want it in newbie/laymans terms of the ins and outs. TIA