Gibbon's The Artillerist Manual, says that the prolonge could be used to retreat or advance by hooking the gun to the limber with the prolonge.

I have heard of retreat by recoil, but can't find the reference right now. As I remember it this was done in roadways and the cannoneers did not bother to return the gun into battery, but fired from the position the gun recoil to. Two advantages, one you are moving away from the enemy even if only a little bit, and two you save time between shots since you do not lose time returning the gun to battery.

These are last resort types of measures that are used to buy time.