I know the CX people at the Ocean Building office. Please let me know your original first ticket's routing, fare basis, booking code and fare.

If you're trading in the first ticket in exchange for an MCO, the 'correct' way to do it is to refund the first ticket and they have to send it back to the original issuer of that ticket.

But if you're rerouting the ticket , ie hoping to exchange that full fare ticket for a RTW, then you can't really. Because they're both of different fare basis'. You'd basically have to make a booking for an entirely new ticket and get it issued instead.

Have you considered issuing the ticket from BANGKOK? Fares there are at least 15% lower than Singapore on average!