How to reset user's Unified Messaging VoiceMail PIN via PowerShell

This one is so easy that I won't type too much :)

Set-UMMailboxPIN  -Identity USERNAME

Most used parameters:

• Pin: use this parameter to manually set a new pin to the user
• SendEmail: set this parameter to $false if you don't want the user to receive an e-mail with the new pin. The default value is $true, which means the user will receive an e-mail with the new pin and information about phone access numbers
• NotifyEmail: specifies the email address that the automated email will be sent to
• PinExpired: specifies whether the new Pin will be treated as expired, which means that the user should change it at the first log on.

More info:

Set-UMMailboxPIN cmdlet