Go to Resource Planner > Find the class
Click on the class
Click on the three dots > Click on "Change repetition"
You have the possibility to change:
Interval and days
How often the class should repeat
If bank holidays should be excluded or not
Time
Resources
Number of participants
Internal and external message
The process to make changes is the same regardless of what you want to change
Mark the class you want to make changes to
Click on the button that matches what you want to change
When the changes are done, click on "Perform"