I-94 card remained in the passport

[Salima]

Hi
My parents stayed in USA for two months and left. My mom realized that she still have the departure card on her passport. They took my dads and forgot moms. What do I do in this case?
Pls reply
Thanks

[immihelp]

Read https://www.immihelp.com/returning-u...4-form-to-cbp/