It isn't possible to quickly send a reminder in bulk to parents to let them know their appointment times.
If you want to send out a reminder in bulk, you can:
- Create a User Defined Field and populate this with the appointment times. Once you have done this you can send a mail merge with the user-defined field as a mail merge field.
- Send emails to parents individually from the guardian consultation page. Our Setting up Parent's Evenings (Guardian Consultations) guide explains how to do this.