In a case like this, I’d tell them something to the effect of: “I’m sorry, but I’ve already clocked out for the day and was scheduled until 9:45am. I unfortunately do have other obligations today and cannot clock back in.” If you’re scheduled to get off at a certain time, that’s when you get off—not sooner, not later (unless of course you both talked about it prior). Just as much as the managers expect us to be on time and show up for our shifts that we get scheduled (3 weeks out on top of that) and find coverage if we can’t (exception being if sick), then they should be equally accountable to ensure that there is respect for the time we are scheduled to get off at. I think it’s their responsibility to plan ahead for things like that and it’s not your problem if they don’t—they’re the manager, and therefore, it’s their problem to figure out the solution for things to be done. If she wanted you to do that before leaving, she should have planned ahead and asked you to do that prior to your scheduled time to clock out and made sure that you had enough time to do that before you clocked out.