If you have flights or events crossing the date line from West to East and need a day duplicated, you can go into the Trip Settings and check the box next to Cross Date Line West to East.
1. Go to Trip Settings
Clicking on Settings or the name of the itinerary will take you to the settings!
2. Check the box
The International Date Line feature will be at the bottom of the settings:
Once you have checked this box, you can click the "Save Changes" button to view what it looks like for your client. Here is an example of the client's view: