You can change the name of the event at any time.
This can be done during the meeting by clicking on the current name of the event (in the left part of the top panel) and entering a new one.
Press "Enter" to save.
To edit a meeting, go to the Meetings page, select the event you want to edit, and click on the name of this metting.
Enter new changes in the edit form. Click the "Save" button.