This cuts both ways. Yes, be grateful she has a job, many who need one don't. Yes, be crabby they are jerking you around, that's a crummy way to be treated.

Your best bet is for her to work as agreed, but she should CALMLY speak to a supervisor about the difficulty in adjusting her life to so many drastic changes. If she is calm, dignified and speaks in a rational manor, chances are good that someone will look into this rather ridiculous flip-flopping of her work schedule and if things go your way, they won't let it happen again.

This method worked for me very well with three different managers. Sometimes the lead supervisor has no idea what the scheduling person does, as long as the positions get filled when they need to be.

Besides, it's just another day of the week. You can easily make any day something special, the calendar doesn't control that.

Gale