How To Reduce My Supply For Exclusively Pumping Mum

Hi, I am at 5. 2th months breastfeeding now. I used to pump every 4 hours but lately my baby girl is going through phases where she refused to feed, refuse to sleep. I cut my pumping to only 4 times a day now. Means I pumping every 6/7 hours yet my supply is 900-1000ml per day. How to reduce it? My baby drink only 700-780ml a day and I do not want to store the milk.