The braid line on one of my reels is getting worn on the end and I'd like to reverse the line on the same reel.  Is there an easy way to do this?

You just have to transfer the line from one spool to another an odd number of times. If you have a spare spool for your reel, pop off the full spool, and spool up the spare after putting it on your reel.

If you don't have a spare, don't just strip off the line and switch ends, you'll end up with a big knot. Take an empty line spool, attach a hand drill, strip off the line. You'll then have to transfer the line once more before attaching it back to your reel. You can even use 2 empty reels instead of an empty spool that used to have new line on it if you have it.

I just walk it out in my back yard...

I use a couple of my old decommissioned baitcasters specifically for this purpose. Works like this:

1. Tie line to old baitcaster #1.

2. Reel line on to old baitcaster #1.

3. Tie line to old baitcaster #2.

4. Reel line on to old baitcaster #2.

5. Tie line on to good reel

6. Reel line on to good reel.

- Done - 

Two empty spare reels.