lordheetsink,
Well, you would go to Voice Processor > Timers and Limits > Timers and Limits: Maximum Greeting Length [Default: 1 min].
If you are referring to Mailbox though you would go to the individual mailbox and change its message length there, but since you stated it was a minute I assumes you meant Recording length for CRAs.
Mailbox
Voice Processor > Devices > Mailboxes > MB # > Message Limits: Maximum Outgoing Message Length [Default: 5 min]
Thanks,
TE