Thanks to the "Do Not Disturb" mode, the LG device can be muted during an appointment, provided that an appointment with start and end time is entered in the calendar. If a new appointment schedule is created in the "Do Not Disturb" mode of the LG device, the calendar can be accessed. Here you can select the calendars of the different accounts. The mode also allows you to choose whether the LG device should be muted for all, perhaps attended or participated appointments.

Android 9 | LG UX 9.0
Step 1:  Open the  Settings
Step 2:  Tap on  Sound
Step 3:  Tap on  Do not disturb
Step 4:  Tap on  Add schedule
Step 5:  Tap on  Calendar
Step 6:  Adjust the  settings  and tap on  Save
  1. Open the Settings
  2. Tap on Sound
  3. Tap on Do not disturb
  4. Tap on Add schedule
  5. Tap on Calendar
  6. Adjust the settings and tap on Save

LG Instructions