How do I move money from one address to another on the same wallet? My wallet have 3 addresses. I want to consolidate payment into one.

What should I do in bitcoin-qt.

Notice on the SAME wallet. I know how to do this if the addresses are on different wallet.

I just don't want to keep moving wallets because I have backups on those wallets.
Create a new address and send your entire balance to that new address.