You don't need the outlet anymore? Unless I'm not understanding what you want to do, I'd disconnect the outlet and remove the box. Put a blank face on the box and replace it. Then fill the gap with a drywall patch. You might have to cut a large hole in the drywall to access the conduit connections. The original box will become a junction box.

If you do want to retain the outlet, do what I said then add a new box for the outlet. Knock out the appropriate number of holes in the old box, and run cable (not pain the ass conduit) to the new box.