Yes, you can amend the date and time of one or more sessions in a series quickly and easily. Just go to the desired session on your Schedule (or the earliest future occurrence of a series) and drill in to the session settings by going to Details>Edit this session. Scroll down to the date and time settings and amend these to the new date and time.
If you are just updating this session, then click Update this session. To update this session and all future sessions in the series then click Update all sessions in this series. If you are wanting to update only a select number of instances of a series then tick Update this session and selected others, tick the desired dates on which you want the sessions to be changed and then click Update selected sessions.