Yes, you can edit date and time of the class anytime later. Follow the below given steps:

• Select My Classes link from drop down menu of My Stuff. Here you will see the list of all your classes.
• Find the class you want to edit and besides the class title click Edit.
• From the left navigation, under Quick Links select Change class time. For the recurring series select the appropriate class from the drop down menu of Select the class.
• Edit date and time and write a message for class attendees.
   

New date and time of the class is updated and an email is sent intimating all class attendees about this change.