BREASTFEEDING TO BOTTLE FEEDING

hello momshies. can anyone suggest on how to train my LO sa bottle, he's turning 4mos and need to go back to work but tnry ko sya e bottle fed kahapon ayaw nia ?.. na mix feeding ko nman xa from birth til 1 1/2 month xa kaso na admit xa ng 1month at inadvise ng pedia na breastfed muna den now na uli xa ng bottle.