One question on REO's please

Hello to you all, HAVE AN IMPORTANT QUESTION:
I have flipped several dozens of homes over the past 20 years, the old fashion way (purchase, fix-up, and sell). I am fortunate to have a great realtor/s, a great title company (who I asked last week, and will honor assignments),etc... I am new to Dean's strategies. I have started my list of investors through research of a cash buyers list from my realtor, and researching through the tax sites!
QUESTION IS: I believe I understand how to do this with a private owner, but with REO's everywhere!, how do I approach the BANK with a low offer and TIE UP the deal for one of my investors? With no money down, does the bank need to or Have To know I am doing an assignment contract? How to do this??
Hope this isn't asking too much of you to answer.
SO ANXIOUS TO GET STARTED!
sincerely, Scot in FL