Owner FInancing on a Home with a Mortgage

I have been receiving inquiries for the purchase of one of the homes that I am selling and these buyers want to do owner financing. However, I currently have a mortgage on this property and do not really know how this works as I know this loan can be called due at closing. Does anyone have experience with this? Other offers have been cash, but low and not really enough to even cover the mortgage that is currently on this property. Any advice is greatly appreciated!