A flowing transition move
1° Launch a fast endo and bring your knees towards the bars to absorb some of your momentum. Lean forward and concentrate your weight above your front wheel.
2° Once you have transferred your whole body on the front, release the front brake and roll off the bike forward in one swift extension from the arms (to release your momentum).
3° Finish off the move fully extended again, lifting the bars in front of you to maintain the front wheel off the ground after it rolled. Stretch with the rear wheel beneath you.
See this move in a video
The wheel-swap is easier when you launch it with plenty of forward momentum, like doing a fast endo that would go over the bars if you didn't release the front brake. Try it out on a kerb to gain confidence, then build it up on narrower edges. The trick is to shift your weight forward and above the front wheel (knees below the handlebar) and then whip the bike forward (the actual wheel-swap) by extending your arms while your body stays on the same spot (over where you push your back wheel).
Just keep your body moving
It is like decomposing your forward momentum into small bits that you reuse it in your own time.
Once you understand the concept, you can even do a back to front wheel transfer on the reverse principle. Try it just for fun. Some guys will bounce off rails and narrow edges... Same technique, just bloody difficult. Although it makes it more difficult, you could do a wheelswap on the spot just by emphasizing body movement.