You've already added a date override for a day when your availability changes, but now you want to add another override for that same date. When you try to add a new override, the date appears greyed out on the calendar, so you can't select it.
To add another override for the same day, just click Edit next to the existing one (you’ll find it listed under your date overrides). In the window that opens, head to the “Which hours are you free?” section — from there, you can add as many time slots as you need for that date. Be sure to save your changes by selecting Update Override.
