What happens to alimony clause in a sep agrmt if reconciled

I know that you cannot waive alimony in a post nuptial agreement in NC, and so if there was a sep agreement that waived alimony and then the parties reconciled that part would be void. But what about a sep agreement where alimony was not waived? For example, the alimony consists of a single one-time lump sum, that has been paid already, and then the parties reconcile. if they were to separate in the future again, would it the previous alimony that had already been agreed to and paid stand or would the ex be able to try and get more alimony. Is there a way to word such a one time distribution of alimony in an agreement such that it is final and binding between the two parties, even in the event of a reconciliation?
Thanks

RH

Since the parties would still be married there would be no other agreement to enter but a “post nup”. Since alimony cannot be waived in a post nup, the subject of alimony could be re-opened in the event of a failed reconciliation.