I don't see any reason why it could not be. When I got my college ring many many years ago, they mispelled my name on the engraving on hte inside of the ring. I took it back and they sent it back to the company that made it and I got it back in about 10 days or so with the correct engraving.
The problem would be finding someone that would do it for you. Looking for goldsmiths in your area would probably be your best shot. Just remember that most custom reworking on antiques carries no warranty.
The switch knot is a decorative lacy macrame/ hemp jewelry knot that helps you save on twine too. This tutorial shows you how to tie one with clear pictures and instructions.
A sliding knot is a wonderfully easy way to end off a leather, string, hemp, or corded necklace or bracelet. It looks neat and stylish, is a very practical closure, and is very easy to make.