The one that happens most frequently is if a sale is made within X days after the cancellation, the listing agent is still guaranteed his/her commission, and also some agents require that X days pass after the cancellation before another agent can relist the property.
They may present you with a list of buyers that they want to get paid if you sell to them. Or they may say if it sells to anyone before the end of the original listing they get paid- or they may want you to leave the sign up for their publicity or many other things. Anything that is legal, ethical, moral and agreed to by both of you could be true. They do have some leverage because you did sign a listing agreement.