Changing alimony after divorce

My divorce in NC was final in December 2010. I have 21 months of spousal support remaining to pay, based on the separation agreement that we signed and had notarized when we separated. If we both agree, and modify the separation agreement, and have the modification notarized, could I pay the entire remaining amount of spousal support in one lump, and if I do that, am I opening myself up to any potential negative consequences that I am unaware of? Or is it too late to modify anything, since the divorce is now (thankfully) final.

(I am paying child support as well, which I understand would be totally separate, and I would hesitate to alter those terms, knowing she can seek a readjustment any time the situation changes, that would totally ignore whatever we agreed to in an agreement.)

Thanks for any advice you can give.

Parties can modify a contract between the two of them at any time, so long as they both consent. I would be hesitant, as the payor, to pay alimony in a lump sum as you lose the chance that your obligation could terminate sooner based on cohabitation, remarriage or death.