Can you remind me in a month that I have a dentist appointment?
user
Sure, I will add it to your calendar.
assistant
Don't you need a time for the reminder?
user
I do have a fixed time, but I also show the reminder a month from today.
assistant
Can you remind me in a month that I have a dentist appointment?
user
Sure, I will add it to your calendar.
assistant
Don't you need a time for the reminder?
user
Sure.  May I suggest you choose the dentist appointment at 5:30 PM?
assistant
Can you remind me in a month that I have a dentist appointment?