I'm not talking about my availability, I already know how to do that. I'm asking if there is a way I can change how many hours I have to work in one week online. Right now they have me working 26 hours and I would like to work 15-20.
You can't be forced to work more than 8 hours per day, so just tell them you are unavailable 4 1/2 days per week. Then you'll be guaranteed 16-20 hours per week.