mistake on DS-156 - new appt date required?

[info_seeker]

On my mother in law's DS156 the date of issuance of the passport is wrong (the appt is at Mumbai consulate). If I attempt to correct this by "retrieve/modify an existing application" through the VFS website, will it require me to take a new interview date by cancelling the current appt. I would like to keep the existing interview date the same.
Whats the best way of correcting it?
Please help.
Info_seeker

[immihelp]

You can keep the same appointment.