Can one parent unilaterally end a parenting coordination arrangement?

Whether one parent can end parenting coordination unilaterally depends on what the parenting coordination agreement itself says about ending the arrangement; there's no universal rule that applies regardless of what was agreed. Some agreements are written to allow either parent to withdraw with notice, recognizing that continued participation should ultimately be voluntary, while others require mutual agreement to end the arrangement, or tie its continuation to a broader separation agreement or court order in a way that makes unilateral withdrawal more complicated.

Where an agreement does allow unilateral withdrawal, a parent who ends the arrangement without a workable alternative in place may find disputes reverting to informal negotiation or, if things go poorly, the court, since the coordinator was presumably filling a real gap. Before ending a coordination arrangement unilaterally, it's worth thinking through what will actually handle the next dispute, since simply removing the coordinator doesn't make future disagreements disappear. Reviewing your specific agreement's termination terms with a family lawyer before acting is the safest first step.