formula feed.

Hi mommies. Any suggestions po on how I can train my son to drink formula milk. I started to work 2 months ago and my milk supply has decreased. Bumaba nadin po timbang ni baby kasi hindi sya nakakainom ng tamang amount ng milk for 8-10 hours na para po sa edad niya. My son is already 1 year old. I tried changing his milk pero ayaw po talaga niyang inumin. Hoping you can give mo some suggestions. Thank you! God bless everyone.