This flight change happened last year for the KUL return flight, and has happened again today! The main problem is it means i arrive a day early for my connecting flight at LHR (!). Quick call to YouFirst and they advised that the KUL flights in First almost all fully booked, i could either keep the revised booking (and lose a day)or move to Sat night flight (another 3 days in KUL!). Was also offered the option of flying out from SIN, but had to make my own way there. Also, worth having a look at the Fare Code that has been applied to your amended booking...