Make sure that the changes to your event are not lost by saving in Google Calendar.
When you’re finished filling in the details, save your event:
Step 1: Click save.
Step 2: In the pop-up, click Send to notify guests by email, or Don’t send if you don’t want to notify guests at this time.
To update existing events:
Step 1: Click the event in your Calendar.
Step 2: Click Edit event to make changes, such as updating the time or inviting more guests. You’ll also be able to see which of your guests have accepted your invitation.
Step 3: Click Save