You can edit a meeting that you've scheduled just like any other appointment—however, when you’re done, you need to send an update to the invitees.
Double-click a meeting you created in the calendar to open it.
The meeting window opens in Appointment view. You can make changes in this view or click the Scheduling Assistant button on the Meeting tab to make changes from there.
Make the necessary changes in either Appointment view or Scheduling Assistant view.
Click Send.
A meeting update is sent out to everyone involved in the meeting with the new date or time.