S.B.
I would request that the owner be present as well. If not, get another manager to be present. Do NOT go into a meeting alone with her. You need to have a witness to this "meeting". If she asks you to sign any type of discipinary action do NOT. That is admitting that you agree with whatever is on the paper. Have her write "refused to sign". Get a copy and respond to any allegations that are in this corrective action. Be professional and non confrontational. I would not apologize for the whatever comment. You can get around that but again be professional and non confrontational. If she becomes hostile or unprofessional, cut the meeting short.
Document document document!!! If she fires you, you can give documentation to the Unemployment board. Also, if other employees will sign statements to her behavior I would get those as well. Good luck!