Baby hates formula

Jazzy
Hello glow moms! I've been ebf'ing my baby for almost six months but the time has come to give him formula to supplement while I'm away at work (not able to pump enough). Problem is, he refuses to drink formula! I've tried two different formulas (baby's only organic and Similac advance) and he just turns his head away. 
Any moms who have been in the same boat and/or suggestions on what I can do to help ease him into drinking formula?
Thanks in advance!