Ask. She might tell you she needs you to wait though (until a new shift is trained). Generally, you would transfer to another store.

I am personally going through this process myself. I would recommend discussing it with your DM, especially if you afraid of retaliation. Your DM could even sit with you while you talk to your SM if that would be helpful.
Whether or not you stay as to your store is really up to you. I'm staying at my current location, though my SM has been really supportive and even has helped me negotiate a better wage when stepping down. I also have 3 other baristas at my store that use to be SSV's (demoted this and other stores) so I have a good amount of support. If you don't have that, transferring might be easier because you get a fresh start and no one expects you to do things above your pay grade.
If they try to force you into a situation that you don't want, call partner resources and get your PR contact involved. Sometimes the only way to get Higher ups to listen is to make it obvious to the people above them that there is something wrong. People will do a lot to save face and not get investigated since PR and ethics and compliance can ruin their career