can another person change the apple id on the main phone

Jazzmn010 wrote:

when you set up family share can the other person change the id on another phone

Family Sharing is not a master key to other Apple IDs or to other devices.

The organizer invites specific Apple IDs, and not specific devices.

Only the member Apple IDs can share (specific) things, when and as enabled.

Members do not have access to the iCloud data of other members, except that explicitly shared.

There are some opt-in controls available for parents to restrict certain things from members that are youngsters.

Some info: Family Sharing - Apple

I am not completely clear as to what you are asking but you would have to have physical access to the other device in order to change the ID on it. A person can erase a device remotely but cannot sign in on it without physical access. In order to erase it they would have to have the sign-in information for the account on the device.