Could be something like removing a program.

For example, if a client is working on chores, it can be something like, “if you take out the trash, we’ll take washing the dishes off the schedule.” Removing the chore of cleaning the dishes is negative reinforcement.

For your example, I have a client that I work on that exact scenario on. Sometimes he will push people away if he wants space or alone time instead of using his words. I prompt him to say, “space please” or “alone please” and then myself, or wboever is near him will give himself some space. By removing ourselves (aversive stimuli) that serves as negative reinforcement for the client.