I am unable to update calendars

Hello Cliff,

From what you've shared it sounds like your Calendars are not syncing as expected across devices. If that is correct we recommend these steps.

"Calendars and Reminders

To check which account your calendars are in, open the Calendar app, then tap the Calendars tab. 

Set an iCloud calendar as the default calendar:

1. Tap Settings, then Calendar.
2. Tap Default Calendar. 
3. Tap a calendar under iCloud to make it your default."

If your iCloud Contacts, Calendars, or Reminders won’t sync - Apple Support

Best regards.