When there doesn’t seem to be any progress, it may be wise to postpone the negotiations. When the other party is postponing, you may create urgency. The other party says, "I’ll get back to you." Let other parties know what they have to lose.
But to create long-term relations, you need to be sure you are giving the other party a good deal. Honesty is the best policy. Establishing a relationship of trust is the necessary first step in closing a deal. If you do have other options, you can use them to create urgency.
When you want to postpone, the other party may create urgency. If you are not satisfied with the deal, or want to shop around, tell the other party you want to think about it. You may also need to check with your boss, or someone else, which simply may be for advice, before you can finalize the deal.
If the other party is creating urgency, be sure it really is urgent. In any case, you may get the same deal at a later date; don’t be pressured into making a deal you are not satisfied with or may regret later. If you do want to postpone, give the other party a specific time that you will get back to them, and then do so. Whether it is with more prepared negotiations or to simply say you cannot make an agreement.