You are likely integrated with a third-party directory such as Active Directory or Netscape/Sun iPlanet. Changing various user parameters (such as passwords) will be disabled by default on these integrations.
It is recommended to reset the password from your directory's administration tools (AD Users and Computers for Active Directory, whatever the tool's called for the Netscape directory and friends). If you cannot do this, you can override the restriction by changing a registry key on CallManager. After setting this and restarting IIS, you should be able to reset passwords from CCMAdmin.
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