Negotiators always have to deal with the simple fact that a negotiation is never over, until it’s over. 

What this means is that it is possible  that after months of negotiation and the use of a wide variety of  negotiation styles and negotiating techniques, you reach a detailed  agreement with the other side and shake hands. You are all done, right?  Well, maybe not. A week later, the other side’s procurement officer  calls to tell you that there have to be some “revisions” to the deal.  Perhaps they expect you to deliver the same service package faster than  agreed upon and for less money. This happens after you’ve lined up  resources internally and gotten commitments from your own vendors. In a situation like this, you end up trying to make the new deal work, since  you can’t afford to lose these key customers. 

What can a negotiator do when this issue pops up?