1)click this step 1 and scroll until the bottom, then click 'Get Support'
2)select 'repairs and physical damage'
3)select 'screen or display quality'
4)select schedule a call
5) enter your imei

after that follow instruction.
What will happen - instead of you goin physically to any service centre the first time and face uncertainty, Apple helps you to schedule a call back session - Yes Apple will actually call you back!
At the end of the session you should be given a Case ID. Take this Case ID to the preferred Service centre of your choice (determined during your phonecall as well) and just drop the phone together with the Case ID.
As far as i know Malaysian AASP at not obliged to provide spare phones to their customers. Depending on stock/model availlability the replacement (If Apple deems it is necessary to replace) may be between 1-14 days. I have experience receiving an iPhone6S replacement the next day. Your mileage may vary.

Disclaimer - Writer does not work for Apple and Apple has no obligation to replace your device based on whats is written above.