To manage your Copa Airlines reservation, you can visit the airline's website and follow these steps:

1. Click on the "Manage your reservation" tab on the homepage.
2. Enter your reservation code and last name to access your reservation.
3.
Once you have accessed your reservation, you can make changes to your flight, such as selecting or changing your seat, upgrading your ticket, adding baggage, or changing your flight date or time.
4. You can also view your itinerary, check in online, and print your boarding pass.

You can contact Copa Airlines Customer Service by phone or email if you need further assistance. They can assist you with any questions or concerns regarding your booking.