rename home folder and user name

After my recent post my Mac is running much better thanks to ASC help. About 18 months ago I encountered a problem on my Mac and Apple support helped me to solve the issue, but I had to set up a new user account with a different name, I used my middle name. I would like to change the user name and home folder back to my original name which is Roger Riseborough. How do I do this and is it complicated? Your help will be very much appreciated.

Roger