Google Calendar - Moving Events
Here is a video on how to move events, if you prefer.
There are a couple different ways you can move an event in Google Calendar.
Method 1 - Click and drag
You can simply move the event by clicking on it and dragging it to the appropriate date/time. All information stays the same when you do this. This works great if you can see the new date/time when looking on your calendar. It's not so great if you cannot see it. Here are 2 examples of this - one in the 2-week view and one in the week view:
Method 2 - Click Edit to see event details
When you click on an event, you get several options. Click on the pencil icon to see the event details:
You can change the information in the event details as needed: