How to get emergency custody of my child in PA?

My 15 year old daughter had a major fight with her father and no longer wants to live or visit with him. My ex-husband and I currently have joint physical custody of her. I agree that she shouldn’t have to go back with him and am concerned that if she does, her physical safety may be in danger. Even if I did think she should go back to the shared custody schedule that’s in the court order, I don’t think she would do it and I can’t make a 15 year old go if she does not want to. How do I file for emergency custody of her? Will a judge allow her to testify in court about what happened and why she doesn’t want to see him?