Go forward to Message Marks. Go backward to Deleting Messages. Go up to Top.

Editing Messages
****************

To edit a message, type `e' (`vm-edit-message').  The current message
is copied into a temporary buffer, and this buffer is selected for
editing.  The major mode of this buffer is controlled by the variable
`vm-edit-message-mode'.  The default is Text mode.

Use `C-c ESC' (`vm-edit-message-end') when you have finished editing
the message.  The message will be inserted into its folder, replacing
the old version of the message.  If you want to quit the edit without
your edited version replacing the original, use `C-c C-]'
(`vm-edit-message-abort'), or you can just kill the edit buffer with
`C-x k' (`kill-buffer').

If you give a prefix argument to `vm-edit-message', then the current
message will be flagged unedited.

As with VM Mail mode buffers, all VM commands can be accessed from the
edit buffer through the command prefix `C-c C-v'.