After a meeting is created you can always change the auto-notification settings for the meeting.
Go to the meeting screen for the subject meeting.
On the left side of the screen, find the Meeting Data block.
Find the Auto-Notification Settings. If your access privileges allow you to change the auto-notification settings for the meeting, a Change Email Settings link appears below the current settings.
Click the link to display the settings editor
Make your choices to changes the settings and click the Save Email Settings button.