What Options Do I Have When the Father of My Kids Refuses to Follow the Visitation Schedule?

Q: “The kids father gets the kids for an extended school recess this year. However, in this recess period my birthday and a holiday occurs. I am suppose to gets the kids on my birthday 10-6 and the holiday 10-6 this year. It seems I will be interrupting his extended period with our kids. He is arguing that it is not right and he will not interrupt his extended time for the two dates. His birthday is Jan 1st therefore he always get the kids on his birthday 10a-6p even when it is my extended time with the kids in even years Christmas 12/25 12pm to jan 1st 10am and then they return to me at 6pm. I tried to use this as an example but he is refusing to listen. I made plans on the holiday and my birthday this year which I am forced to cancel because he will not turn over the kids. I was told we can have a lawyer review the plan and break it down so that there is a better understanding but he refuses and states that he knows what he is talking about.

A: “Send a default notice letter, stating if he does not produce the children on the designated days, you will consider it a violation & will take appropriate legal action. If he then violates, you may then file a Violation/Enforcement Petition. Schedule a consult with a Bronx Child Custody attorney for a full assessment.”