Consider two factors when making changes:
Whether the individual Student Accounts and Enrolments have been created
Whether the group has been invoiced or not
These factors influence the steps to take, outlined below.
Note it is much simpler to make changes to the Group prior to creation of Student Accounts/Enrolments and prior to invoicing.
Therefore, generally wait until the group requirements have been confirmed before creating the Student Accounts/Ernolments and invoicing.