I've just received email from SQ that my Feb 2019 flight has been changed from SQ007 to SQ037. It arrives in SIN at 08:15 (2:15 later than SQ007) so I will have to have my SIN-MEL flight changed as well (from SQ207 to SQ217). At the moment I cannot retrieve my booking, as the website can't find it. I will try again tomorrow and if it still fails will give them a call.