The Article Buffer Top Select Methods
All commands for posting and mailing will put you in a message buffer where you can edit the article all you like, before you send the article by pressing C-c C-c. See Top. If you are in a foreign news group, and you wish to post the article using the foreign server, you can give a prefix to C-c C-c to make Gnus try to post using the foreign server.
Also see see Canceling and Superseding for information on how to remove articles you shouldn't have posted.
The Article Buffer Top Select Methods