The Power of Maybe
If you are negotiating in win-win mode, "maybe" keeps the door open to add value items until the entire deal is clearly structured. When two people sit down at the negotiating table, they each usually have a list of items they must have, ones they'd like to have and ones they'll take if offered. One form the negotiation can take is for both parties to exchange lists, then discuss each item.
Excerpted from Creative Selling: Boost your B2B sales