The trial close
There comes a point when salespeople need to determine whether or not they're better off walking away from a sale.
Source: Professional negotiator Michael Soon Lee
One way top negotiators draw the line is by using a trial close. If the prospect is putting off signing a contract and requests another concession, the salesperson can regain control by asking:
"If I can get approval for this one final detail, do you see anything else that would keep us from doing business together?"
It's a question that lets the prospect know they'll work hard to get the details squared away. But at the same time, it puts prospects in a position to make a verbal commitment pending the one final condition being met.