When you have reached the S> prompt, you can still go back a step and work on your message further before sending it. Except for the most casual messages, it is a good idea to review what you have written before sending it, by using the display command.
The command text lets you add to a message in MM's Text Mode. This is the usual simple MM editor. You can change existing text only by using backspace/delete to wipe out text and then retyping forward.
S>text Message (End with CTRL/D or ESC Use CTRL/B to insert a file, CTRL/E to enter editor, CTRL/F to run text through a filter, CTRL/K to redisplay message, CTRL/L to clear screen and redisplay, CTRL/N to abort, CTRL/P to run a program and insert output.):
As shown above, the usual Message... prompt appears. The cursor is at the end of the existing message, but the existing message is not shown. If you want to see where the cursor is (particularly if you need to backspace into the existing message), type control-k or control-l to redisplay the message.
The variable display-outgoing-message, normally set to no, controls the display in this situation. Type set display-outgoing-message yes, and save it with the save-init command, and then when you use the text command, you will see the whole message displayed, with the cursor at the end.
If you know Emacs, the command edit is a better way to go back and touch up a message. It sets up an Emacs screen identical to the one you get by typing control-e at the Message... prompt. You can use Emacs commands to manipulate text in variety of ways until you are satisfied with it.
You can specify edit text or edit headers, and you will get an Emacs screen with only one window containing either the message text or the header fields. The simple command edit is the same as edit all, meaning both text and headers, although the cursor is placed in the text window.
Typing edit headers, or moving the cursor to the headers window of the usual two-window screen, is one method of changing the addresses and subject field of your message, but be careful to preserve the formatting.
If you have set the variable use-editor-always to yes, then there is no difference between the text and edit commands: they both will start Emacs.
The command spell runs a spell checking program called ispell. A typical ispell display follows. The misspelled word meett is shown at the top, then any correct words that are one letter different, and then the line containing the word, with the word highlighted if possible (shown here as boldface). For more information, type a question mark to see the ispell help screen. Note that you can quit ispell two ways: one way saves the changes you make, and one way leaves everything as it was.
meett File: /f/u1/d09200/jb51/.mm-spell.15293 0: meets 1: meet Let's meett on Sept 21 at 2:00 to go over plans for this semester.