How do I stop my ex from moving my daughter out of state?

My ex is wanting to move my daughter from Atlanta, GA to Mobile, AL because this is where she grew up and wants to move closer to family. My daughter is 9 and all lived together for 8 1/2 years. I have joint physical custody since our divorce in 2007. I know I need to file a petition for modification. What do I need to file as to prevent her from taking my daughter out of state? also there was no parenting plan in our final judgement as to the visitation schedule, and my ex is not giving me equal time, how do I get fix this.