What does Rita cancel when she accepts Randy's whiskey?

Rita cancels any claim she has on Randy.... the two once had a relationship.... it was over.

As he pressed the starter Dan said, "Why did you give her the whiskey?"

"I feel sorry for her." That wasn't the only reason. If he had owed her anything before, he did no longer. They were quits. They were square. "Is she going to be all right?" he asked.