To change the lesson start and end times on the Calendar view, click on either the start or end time and select a new time. Selections in the dropdown are in 15 minute increments, but you can also type in a custom time including the AM or PM. 

Both the start time and end time can be edited independently. Most of the time, editing one value has no impact on the other. However, if one value is changed, and it causes the start time to be after the end time, then the other value is also updated.

Start Time Occurs After End Time

When changing a start time that occurs after the end time, the end time also will be updated to preserve the original duration of the lesson. The example below shows a lesson that occurs from 9:00 AM to 10:00 AM on the left. The image on the right shows what happens when changing the start time to 11:00 AM. Doing so automatically changes the end time to 12:00 PM so that the lesson still has a duration of one hour.

End Time Occurs Before Start Time

The same is also true when changing an end time to occur before the start time. The example below shows the same lesson from the example above, but this time, the end time was changed from 12:00 PM to 9:00 AM. The image on the right shows that the start time was automatically changed to 8:00 AM so that the lesson still has a duration of one hour.