I ordered a hardcover book and added a requirement for the dust jacket to be present.  I don't usually have that in my RCs, but would like it for this one.  The person I requested it from doesn't appear active (no profile, no other books on shelf, no WL).  I want to take the dust jacket requirement back out of my RC so other books don't have that requirement.  I know that it won't affect the current request. 

If the request times out, will the RC from the original request (must have dust jacket) carry over to the next request or will I have to keep the expanded RC until the book is mailed by someone down the line?

Yes, if the request rolls over to a new sender, then everything about it, including the alternate address (if you used one) and the RCs will remain the same. If the book goes back onto your wish list, then you'll have to wait for it to be offered to you again in order to reapply the RCs and the alt. address. For this reason, you should make sure it's not on auto-request if it's on your wish list.

Cool, thanks.  It isn't WL - there are 19 copies available beyond the one I am waiting on, so hopefully someone will have the jacket. :)