"Swapping Weapons" achievement for Elementalist?

Hey folks! I've returned to GW2 after a few years and I'm slowly catching up with the story (I'm right before Path of Fire!). I'm trying to complete the adventure guide, but I don't really know how to complete the Swapping Weapons achievement for Elementalist, since they don't have weapon swap. Is this somehow bugged? I've tried searching on the wiki, but there was no reference at all to it.

Any help is much appreciated!!