From your event calendar, simply click on an existing event title, and drag it to the new date. If an event time is set, the new event will start and/or end at the same time on the new date. If the event spans multiple days, the new event will span the same number of days.
Event registrations will not be copied, but all other event information, ticketing, registration, and advanced settings from the old event will be copied to the new event.
Once the event is copied, you can edit the event as necessary to make any adjustment or changes.
Note that you should edit the event title/date within the first 10 minutes of copying the event, in order for the event URL to reflect the correct event title/date.