Oops, my apologies - I thought it was more recent than that (but I haven't ticketed a xONEn since August 2008).

But even so, all you have to do is change your reservation - you could probably do that even when you arrive in SIN (I assume the definition of "no show" is not cancelling the reservation before the check-in for the flight closes).

Reservations and ticket coupons are separate things. The only thing you have to be careful of is that your subsequent reservations don't get cancelled.

This is yet another example where having a paper ticket would make life easier than an e-ticket (where reservations and ticketing are rather too closely linked for my liking).