jenicamartin1308 – https://airlineofficenearme.com/blog/how-to-add-a-person-to-airplane-ticket/

It is usually necessary to purchase a separate ticket for the individual in order to add them to an existing airline ticket. It is not possible for airlines to add people to a ticket that has already been issued. Speak with the airline directly and purchase a second ticket to guarantee that both passengers are on the same trip. To match their reservation with the previous one, provide the new traveler’s information, including their complete name and contact details. Securing the same flight is more likely when reservations are made early.