How can I still get credits for my child if the other parent Is claiming him?

I forgot that it was my dependent child's father's year to claim him. Well I tried to amend my return but it keeps getting rejected. I haven't gotten the return back because they want to verify my identity. Because of this it will make my filing status they said to single. And I'd gave to mail in my amend. Because you can't electrically file if you status changes. How can I still get the head of house hold status and get at least some credits for taking care of him all year?