Unfortunately, there is no clear amendment or cancellation policy available. If you have already booked your holiday, login to your First Choice account and visit the Manage my Booking section. There, you will see the associated fees for cancelling your booking or amending it (changing the name of a passenger, adding a passenger, changing dates and more).
If you have yet to book anything, please pay close attention to the terms and conditions of your booking in relation to cancellations.