so my idea was to do reset books in the vx shop for job class. 1 is reset job + sp but keep level and sp, 2 is reset job ,sp and ap but keep the amount for your level and 3 is reset level , job,sp,ap to 1 but keep old job(s) skills.

with the 3rd option you will be able to stack multiple job classes skills so you can get skill for all classes if you reset multiple times