Spoke to a SQ rep yesterday, I had submitted a request to be routed AMS-SIN but was informed basically all travellers will be proposed a re-routing approx 24 hours out from the cancelled leg - he wasn't sure if this was a rolling daily situation and my flights for the 20th March are still confirmed as far as he could tell (but it looks like they are only reflecting cancellations 24-48 hours out). All decisions come from head office and they were non the wiser. Everyone who had to get to DME were provisioned alternative flights to reach their destination and same would be true for passengers heading to SIN.
I'm flying AMS-ARN in 2 days to get a connecting ARN-SIN-CHC the following day.
If anyone has travelled with SQ to SIN out of ARN in the last 24 hours I would be interested in what the routing was so I can prepare myself.