Hi thanks for writing to Practo consult. If baby has no fever, and otherwise healthy, may be he does not want bottle. Just start him on semisolid feed and breast feed to continue. Do read my article it may help you..."Which Weaning Food to Introduce & When!" by Dr. Poonam.M. Sambhaji - https://www.practo.com/healthfeed/which-weaning-food-to-introduce-when-16805/post
Next Steps
In article it mentions 6months, but you can start at 4 months too.