While your agent knows what it will take to make the deal work, you (the seller) are ultimately in charge. If you can't pay the closing costs, and still have enough to do what you want to do... then you can simply say "no".
But recognize that the deal may not gel without them... and decide if you're okay with that.
Have a great day;
CEO & SR Credit & Mortgage Consultant of
Everlasting Credit Repair
Making home ownership more than a dream...
Retired Mortgage Banker
For example if the house is 100,000 and they need 6% add them to the price and give the closing cost instead of bringing the offer down to 94,000. If the seller qualfies for the 106,000 with concessions you are still at 100,000 less your costs. You can also negotoate the concessions also.