Bottle transition

Some things may tell you not to mix it but i gradually mixed the whole milk into the formula, he always had about 6 oz per bottle so I would do 4 oz formula, 2 oz milk then sometimes 2-4 oz of just whole milk. I also still continued to warm the milk slightly and we successfully transitioned in under 2 weeks!

I did the same as above.
My son was on 9oz, so done 8oz formula and 1oz cows milk, then after a few days 7oz formula and 2oz cows milk and so on until he was transitioned.