Unfortunately, it's not possible to add or remove passengers online through the "My Booking" page currently. But don't worry, just reach out to our support team, and they'll handle it for you.
It is important to note that the removal of a passenger is considered as a cancellation of one ticket on the booking, before proceeding with this request, we highly recommend reviewing the cancellation policy to check if the ticket you intend to cancel is refundable.
Regarding adding a passenger, it might be possible depending on availability. Our support team will be more than happy to help you with that. Alternatively, you have the option to make a new booking specifically for the additional passenger.