How long is REO acceptance good for?

[Daniel Fernandez]

Lets say i make an offer with a POF/LOI to the holder of a property (bank). I will also be using transactional funding to double close as I havent found a title company in SD to do simultaneous closings anyway... Lets say i get an offer accepted by the bank. How long is that acceptance good for? I have heard sometimes it is one day. Does that mean i need to line up my end-investor before submitting my offer or are some REO's acceptances good for longer? Am i missing something? Please help