Syntax: modify alias-name new-alias-value

    The modify command is used to replace the expansion value of an
    alias with a new expansion value.

    db> add postmaster "system@thor.example.com"
    [Entry added to database]
    db> show postmaster
    Key         Value
    ----------  -----------------------------
    postmaster  system@thor.example.com
    [1 entry shown]
    db> modify postmaster "JOHN@example.COM"
    db> show postmaster
    Key         Value
    ----------  -----------------------------
    postmaster  JOHN@example.COM
    [1 entry shown]
    db>

    Wild cards can be used when specifying the alias name in order to
    modify one or more aliases simultaneously.