If you are using e-mail to distribute the documents, you will need to send the "new" replacement document to the user.
You can use RM to "revoke" a document that you have distributed. Revoking a document does not delete or replace the physical file, but a "revoked" document can no longer be opened (regardless of the number of copies or where the copies reside).
When you revoke a document, you have the option to configure a message and a "re-direct" URL that will be shown to the user when they try to open the document. The message let's them know the document has been revoked, and the URL can link to a new version of the document for them to download.
Regards
Steve