gnupg: Agent PASSWD

 
 2.6.13 Change a Passphrase
 --------------------------
 
        PASSWD [--cache-nonce=<c>] [--passwd-nonce=<s>] [--preset] KEYGRIP
 
    This command is used to interactively change the passphrase of the
 key identified by the hex string KEYGRIP.  The '--preset' option may be
 used to add the new passphrase to the cache using the default cache
 parameters.