You get complete control over your calendar and can quickly change availability for a day or two at a time (Note: Looking to block off a longer period of time for a vacation? Check out the instructions on give yourself a vacation: Setting vacation time).
1. Navigate to the "Calendar" tab located on the bottom of the screen
2. Tap on the three dots on the upper right-hand side of your screen
3. Tap on the "Manage Availability" option
4. Select "Adjust Upcoming Hours"
5. Block off days of unavailability, or edit custom hours day-by-day, then tap "Save"