First thing is offer the current shift on the app. Get those picked up asap. Then call your manager and talk about this and say you need to change your availability. One thing that I find help if they say no is ask if it will help them if you can then work mornings/nights/mid on this day instead. This offers it up as a trade in the managers mind. Especially if you word it as helping them. If you can say you would be willing to cover at other stores if your availability can’t be met. I also recommend going to the closest stores to you and asking if you can leave a post it by the schedule with your name phone number, and store and your general availability (closing, opening, mid etc) so others can call you if you need more hours but also to se if anyone would be willing to work at your store those shifts. With school starting up again a lot of partners forgot to change their availability for school and might be in the same boat as you so you can see if anyone would be willing to trade.

and change ur availability

offer ur shift

Good luck