@wilsoneee who did the child spend more than 6 months with? (Please do not state it was the same - there are an odd number of days in the year!). THAT is the custodial parent.
if she is, then she has to amend her tax return but the only thing she is passing to you is the Child Tax Credit; any other credit she was eligible for related to the child stays with her. she still files HOH. The depenent care credit can't be passed to you, so filling out Form 2441 on your tax return does not matter. You can't use this child as the basis of filing HOH. Best to complete form 8332 and have her sign - will make things easier.
However, if you are the custodial parent, you get all the tax credits and can file HOH (assumng you have not remarried) . She retains none of the tax credits related to the child and can't file HOH (unless there is another Qualifying Person in her household).
