You can easily adjust the start or end time of an existing event from the Events editor.
⚠️Important: You'll need access to the Events editor cog, which requires certain permissions.
From the platform, click the Events tab.
Click the cog icon.
Click on the three dots next to the event, then click Edit.
In the bottom right, click Date & Time.
Click on Start Time or Finish Time to amend the time as needed.
Click Save Changes.