If you don’t complete a draft for one reason or another, and if the
draft buffer is no longer available, you can pick your draft up again
with e (mh-edit-again). If you don’t use a draft
folder, your last draft file will be used. If you use draft
folders, you’ll need to visit the draft folder with F v drafts
RET, use n to move to the appropriate message, and then
use e to prepare the message for editing.
The e command can also be used to take messages that were sent to you and to send them to more people.
Don’t use e to re-edit a message from a Mailer-Daemon who
complained that your mail wasn’t posted for some reason or another. In
this case, use E (mh-extract-rejected-mail) to prepare
the message for editing by removing the Mailer-Daemon envelope and
unneeded header fields. Fix whatever addressing problem you had, and
send the message again with C-c C-c.