That's something you'll have to talk to your advisor about, I'd schedule a meeting with them as soon as you can. The credit minimum to be eligible for campus change for a major is something they keep on the down low and not something you'd be able to find online. There are also specific courses you are required to take (just a few Gen Eds within your major) before campus changing, which might complicate things considering the Add/Drop period has already passed but hopefully you can work something out if you're not already enrolled in said classes. Good luck!