I have a customer that wants to change from 3 digits to 4 digits on their BCM50. I seem to remember "mistakenly" doing this once by accidentally changing dn lenth from 3 to 4, and that made 221 become 2221. Is this correct? I know I will have to delete and rebuild all the mailboxes, but I am not sure about how to do it for the sets. Thanks in advance.