Whether and how can I correct the effective date on a filed H4 application

[cyf203]

Hi,

My spouse filed my H4 case together with the H1-B application. The H1B has been approved 1 week later and my H4 is still pending ("case has received") for 3 months now. Now, I'd like to change the effective date, which is located on Part 2 3b. Is there any way to do it?

Thank you so much!