When users are migrated from ACM to ACC you will not be able to change the password through the ACC software. The only way you will only be able to change the password is through ACM. Once the password is changed, you will need to break and re-establish the bridge in ACC under "users and groups" and "External Directory" Tab. After the group has been readded a new password should be needed through ACC. The users that were pulled through ACM to ACC will need the groups assigned to them again.