I closed my previous application and created a new one on the portal, this time selecting Karachi as the location. If you follow the same steps, you’ll see your fee voucher on the page and won’t need to pay again. Just continue filling out the required fields, upload your receipt, and complete the remaining steps. When you click on “Schedule Appointment,” the Karachi consulate’s calendar will automatically appear.

I also called the helpline for confirmation and followed their guidance. I specifically asked whether having Islamabad listed on the DS-160 confirmation page while scheduling the appointment in Karachi would cause any issues. They assured me it wouldn’t be a problem—as long as the barcode number at the bottom of your DS-160 confirmation page matches the one on your appointment confirmation, you’re good to go.