How to deal with ignorance in the work place as a new sysadmin?

Okay, here we go…….

Out of all of the admin staff there is one person that sets a meeting reminder in outlook for his requested days off. Yes, he also puts it on the shared calendar also. I’ve asked him why he sets a reminder for a meeting for his days off and he said he has always done it that way. I explained to him that’s why the shared calendar was invented/created. I’ve told him that I didn’t like getting meeting invites or reminders in the middle of the night, but he still does it?

Without me doing paperwork for insubordination, I just want to disable this feature from his email account. Is this possible? I don’t want to create a rule, I want it stopped! I’ve search online, but I keep running in circles.

Thanks