You can leave her on the return to make sure you receive all deductions you may be eligible for. However, you should follow the instructions below to make sure your partner can claim your daughter.
First, log into your return and select the Personal Info tab and then scroll down to the dependent and select the "Edit" or pencil icon.
When you walk through the questions, there is a screen (see screenshot below--may need to click on it to enlarge it) that asks "Do you have an agreement with XXXX other parent?"
From there, you can follow the directions and screenshots attached:
Select Yes, you have an agreement (see screenshot)
On the next screen, "If XXX other parent claiming Joseph per your legal agreement?" (see screenshot), select Yes
You can then continue through the questions to not claim that dependent.
