Thanks for the quick reply. The text on the Mesmerist card in my game only says:
"Once per Events step:
Choose a staff member without a mesmerism token in any park. Add a mesmerism token and move them to your park until the Cleanup step."
I reckon this is not the updated card, then. No worries.
that is the printed card yes. it has been errata'd. regardless though, nothing on the printed card would allow for resetting the staff abilities. The cards in Unfair are pretty precise. Do exactly what they say.