Can a 19mm bb be changed to a 22mm bb?

Answer 1

Unfortunately not, or at least not in any reasonable manner... It's one thing to get a spacer made for the tube welded to the frame which would allow you to use a smaller-than-stock bottom bracket but to go larger you'd literally have to cut the bottom bracket housing off of your current frame, grind the connecting pipes to a larger radius and then weld a larger bottom bracket housing in place of the original small diameter housing.

Keep in mind that if you decide to try this, the frame MUST be made of steel. Carbon fiber or Aluminum will be a disaster. However, as I mentioned earlier this will NOT be a fun ordeal and unless you have extensive welding (and cutting) experience it won't go well.