Adding an applicant later in the appointment

[immihelp]

Sir/Madam,

I am planning to bring my father and mother to US, for that I applied online and got an appointment for my father, without adding my mother I confirmed the appointmet. I don't know what to do now? Is there any way to add my mother to the same appointmet date and time with my father. Pls help me in this.

Thanking you.

[immihelp]

You can't add now.