Barb - I know of no way to remove a name from that address book list.  I
believe that it is a "Most recently Used" list and could clear a name or
names by using other names.  
]To remove a return address begs the question permanently or temporarily.  
First the return address is entered from the information contained in the
user information.  Go to tools> Options> User information and we'll find a
place where you can remove or change the mailing address.  Whatever is there
(name. numberor slogan) is what will print in the return address portion of
an envelope.   However, if you wish to remove it for only one envelope...you
can select the "Omit" button that appears of the Envelope and labels dialog
box that comes up for every envelope.  Hope this helps.