[HELP] Your Retainer has reached the max level...NOPE!

[Felis]

I switched my lv 60 SMN retainer to AST for 40 venture coins and it changed to lv 60 AST.

[LichtNacht]

I switched my lv 60 SMN retainer to AST for 40 venture coins and it changed to lv 60 AST.

That's cool, can you explain how? I bought the Modern Vacation for 40 venture but no options/choice popped up to use it on my retainer. He is back to level 1 Conjurer.

EDIT:
When talking witht that NPC this are the option you have:

"Ask about assigning your retaier a job"
"Ask about job requirements"
"Purchase a copy of modern Vocation"

That's all, i have the Modern Vocation in my inventory but there are no options to actually use it, even on my second retainer still level 60 WHM. If he was lvl 60 Conjurer maybe there was the option to put him the AST soul, but since he have the WHM one i cant.