I will be of no help as my dd was set in her ways and never changed times for us, until the age of 2 and she did it on her own.
You can adjust the day by 15 min. increments a few days at a time and see if that works.
Some lo's just have a natural internal clock and they will wake up at the exact same time every single day no matter what and others are easily moldable...it all just depends on the lo.
Melissa