Upvote:2
You'll have to cancel the appointment and make a new one with the correct passport number.
According to vfsglobal official FAQ:
I made a mistake while booking an appointment or I entered the wrong passport number while booking an appointment. What should I do?
All data submitted while booking an appointment must be correct, otherwise you will not be allowed to enter VFS Global premises . If you made a mistake while booking an appointment, please cancel it through the appointment system. You can book an appointment with the correct information right after.