Using Outlook for iOS in educational settings for communication and organization
Message recall only tries to delete the original message from recipient mailboxes. If recall succeeds, the original email is removed for recipients who had not opened it yet.
The later replies are separate messages. Recalling the first email does not recall those later responses. If those replies were sent normally, they can still be delivered.
A replacement message is different: if the replace option is used, Outlook deletes the original message and then sends the new message as a normal delivery.
The recall result is confirmed through the Message Recall Report, which shows whether the recall succeeded, is pending, or failed.