Once your ticket is paid in full it is generally not possible to ‘re-route’ unless you are on a Round the World ticket.
A "Round the World ticket" is where all flights are on 1 ticket number only. If you have flights which go around the world but the flights are on separate tickets, it is not classified as a "Round the World ticket".
Any route changes are subject to the specific rules of your ticket, availability and any applicable amendments fees, additional fare and taxes.
Please contact the store where you booked to make a request. Their contact details are on your documentation.