Selling/Pawning diamond engagement ring?

Keep in mind the engagement broke off for personal reasons. Anyway, if you need to sell/pawn the ring for a really good reason. Can you sell or pawn it to a jewelry store? Or if you returned the ring to the store it was bought at. Well they give you the money that was paid for the ring? Or do they just take the ring back? There is a really good reason the ring needs to be sold and or pawned and I know you don't go to a pawn shop for such things because you get squat for it. So I am trying to figure where else to go.