I completed the support job quest and went to my Mog house. A level 20 Monk, I declared Thief as my support job. Today I wanted to make Thief my main job in order to begin leveling up in it. When I try to change jobs (Thief from sub to main; Monk from main to sub) I get an error sound and nothing happens. I must be missing a simple step. What am I doing wrong? Thanks for any help/advice.