Can a name change application be blocked if it would harm the child's relationship with the other parent?

Yes — a court considering whether to allow a child's name change over an objection will look at what effect the change might have on the child's relationship with the parent who isn't getting their name added or kept, since preserving that connection is treated as part of the child's best interests. If removing a parent's surname, or replacing it entirely, risks sending a message to the child that the other parent is being erased from their life or identity, that's a real consideration weighing against the change, not just a technical objection to be brushed aside.

This doesn't mean an objecting parent automatically wins — the court balances this concern against the reasons for the requested change, including any evidence about how the child actually uses their name, safety concerns, or confusion in daily life. Where the parent seeking the change can show the child's relationship with the other parent isn't actually affected — for example, because parenting time and contact continue regardless of the surname on paper — that can help address this concern.