asking permission to use a mobility aid at work

I work at a gas station and use a cane. That's ok with them. But my Ehlers Danlos 3 has gotten to the point where I need to use my walker to get around safely and to prevent injury.

How do I ask my workplace if it's ok? This is very scary for me because I was fired at my previous job for using the cane-they claimed no reasonable accommodation could be made. I'm scared because this could happen again.

If y maniger doesn't want me to, do I ask the higher ups who made me sign a release of liability form?

Do I just show up like that?

Any help I would appreciate because I'm very scared on what to do.

Hi! I'm curious, what was your last job? I'm really tired of hearing about how employers here in the states get around the Americans' with Disabilities Act. Always claiming that "no reasonable accommodation" can be made. Do you know that at your local employment agency there should be a state office where you can talk to someone about that? It may be considered an unlawful discharge from a job.

If it were me, I would just use the walker as you have been using the cane before. Don't ask them, thus giving them a way to say they can't accommodate you. Just do your job and see how it works out! Good luck!