Forwarding mail with sendmail

Hello,

I need to forward mail wich are in some users mailbox. The .forward redirection is working for all new mails but not for old. Is someone know how to do this ?
Thanks

If the mail was already delivered, you can't forward it via sendmail. You would have to access the mail and forward it via the client OR you could email the complete mail file to a new users.

Thanks for your help.
I find the solution by myself and use fetchmail to do it.