To know the Copa airlines cancellation policy of Copa Airline, passengers should go through the points given in the following steps:

You can get your refund if you cancel your flight tickets within one day of booking.
The airline charges cancellation fees for canceling flight tickets after the day of reservation and they may be deducted from the refund.
Cancellation of flight tickets is not allowed 24 hours before the departure time of the airline
https://www.flightzticket.com/copa-airlines-cancellation-policy
To know how to cancel copa airlines flight follow the given link.
https://www.airlineticketpolicy.com/cancellation/how-to-cancel-copa-airlines-flight-ticket/