Typically, a seller will have identified his/her next residence before placing the home on the market. 

It can happen that a buyer makes an offer on a home before the seller has made up his/her mind regarding the next home.  If this occurs, the seller has the option to rent a home after closing or to enquire from the buyer on the possibility of renting the home back from the buyer, after the closing, while he completes his move.

If the buyer is willing and can afford to wait, this might be an excellent way to have the seller cover one or two months on the new mortgage.  In this case, the buyer’s agent will draft the appropriate lease agreement, which includes protective clauses stating that the home must be returned to the buyer in the same condition it was in on the day of the closing.