I think if you just offer her the sippies (or even straw cups - they worked best for us at first), with juice/water for a while. If she doesn't take the milk in the cup then fine, just don't offer the bottle. She will be totally fine with no milk for a few weeks, especially if she is getting dairy from other sources. Later, once she's not had a bottle for a while, you may find she will take the odd cup of milk. When ds started on a cup he would never drink milk in it - only water or juice. But, after a while I was able to offer milk and he was fine. I guess the hardest time might be at bedtime if she is used to it during wind down. Maybe if you introduce something else that is novel as a distraction, and give her a cup or juice or water at that time instead for a while.