If you need to remove a child from a master, open the child machine and set the status to Finish.
The master will ignore this machine in the future, however the history for reporting purposes will remain.
If you need to add a child to a master, set up the new child (remember, you can create similar from an existing child) and add the Master# in the child.
This will link the new child to the master.
Set the Next Bill Date as per the Next Bill Date on the master.
Copy the meter setup from the master down to the child by opening the master and clicking Save.