I use Outlook 2010, but I would guess that later versions of Outlook have retained the following option for removing addresses when using auto-complete.  As an alternative approach, you can also go to your address book in Outlook and with the applications key or shift + F10, delete individual listings.  Setting that aside …

For example, you open a new message, and your curser is in the “To” box.  Press the beginning letter of the name, and Outlook gives you that portion of the address book.  As you hear JAWS say the entry, you can simply press the delete key, Outlook removes the entry just spoken, and speaks the next entry in line.  You can continue to press the delete key.  If you come across an entry you want to complete, arrow down to hear the next entry.  You can continue to arrow down, pressing delete on ones to remove, until you get to the end of that portion of the alphabet.  From there, backspace to remove the letter you had typed, and press a different letter, taking you to that portion of the alphabet in the address book.  Continue on as desired.

Hope this works, for me it is the easiest.

Tim Ford