EDIT  -  edit messages in a mail file

Usage: EDIT [message-sequence]
  Unless specified, the message-sequence is "current".

The EDIT command is used to edit a message or set of messages in your
  mail file.  The editor used is defined with SET EDITOR; the default 
  is emacs.  The main purpose of editing received mail is to save 
  only part of a long message, or fix a typo.

Example:			
    MM>edit 10       #edits message 10

For more help, type "help" and one of these topics: 
    message-sequence   set editor   other   text-mode
