Originally Posted by
kayzng
When the above 2 combine, I am thinking to start a new RTW ex-TYO, then I can combine with this RTW from NRT and cancel the rest. But, I am afraid I can't get the new RTW effective if I only start to buy it after I done KUL-NRT in first RTW
Of course you can buy a new RTW wihout regard to any current itinerary which may be in progress. (People here sometimes report having two RTWs underway simultaneously, one 'inside the other' as it were.) If you want to cancel all remaining segments on your first ticket after reaching NRT, you need to refer to the Rules. (You do have a copy of the Rules, don't you?)
Section 16: Voluntary changes / rerouting / penalties
Part (b): Cancellations and Refunds
Paragraph 3: For partially used transportation the refund if any will be the difference between the fare paid and the fare for the transportation used less the fee specified in (1) above.
The reference to (1) specifies that there is a penalty of 10% for L or 5% for D and A