When composing or replying to an e-mail message in Outlook, you can easily rearrange the names of the people receiving the message by dragging their e-mail addresses between the To, Cc, and Bcc address fields. Just select the name or names you want to move and drag them into the destination field.

Note: If you have errant semicolons in the To, Cc, or Bcc fields, you can remove all them by pressing ALT+K.