So, if I buy that setting and size of the stone matches - that wouldn't be an issue to swap that out?
if you buy a new setting and the stone it currently holds is the same cut/measurements as the blue stone, then it shouldn't be an issue to set the blue stone into the new ring.
one common issue with putting coloured stones into rings is that they're often belly-heavy and don't fit into the calibrated settings.
*but* if it was set into the ring it's in now without any modifications then that might not be an issue for that particular stone.
(it isn't always an issue, but it does happen, so i wanted to mention it)
and, from the other direction, if you buy a ChrisCZ in the same dimensions as the blue stone, it should be able to go into the gold ring with no problem.
... that convoluted enough for ya?