CHGPASS

The CHGPASS command is used to change the password for a nickname or operator account.
Changing a Password
Usage: CHGPASS <object> <old_password> <new_password>
<object> The account to change the password for. This defaults to a nickname account. To specify an operator account, use the prefix Operator::. For example: Operator::MyOperAccount. To specify a nickname account when there is a chance of ambiguity you can use the prefix Nickname::. For example: Nickname::MyNick.
<old_password> The current password for the account.
<new_password> The new password for the account.