Appointment: Can U show different I-797

[JMK]

Hi all,
I am planning to visit India (from July 20th to August 10th) and will need to go to Chennai for H1B visa (have worked for a year but had come to the US on an F1 visa).
I have been offered a new job and plan to apply for premium processing immediately (I believe I should know the status around July 10th).
I have 2 questions:
A. Can I go ahead and take an appointment (sometime between July 20th and Aug 1st) at Chennai based on my current employer's I-797 and present the new I-797 which I hope to receive before I travel to India.
B. How early does one have to look to get an appointment at Chennai (since I have never have had an H1B visa, I can not request for expedition/emergency).
Thank you in advance (and, hopefully this situation has not been already answered).

[shervin143]

A. Can I go ahead and take an appointment (sometime between July 20th and Aug 1st) at Chennai based on my current employer's I-797 and present the new I-797 which I hope to receive before I travel to India.
>>> You cannot do that. You cannot modify an existing Ds-160 later. If you want to change anything (receipt number, employer information) you will have to start all over again, which will give you a new barcode. Check the DS-160 sample in immihelp. Moreover, how do you know that your transfer application will get approved and there won't be any RFE's? Wait till you receive the approval notice.

B. How early does one have to look to get an appointment at Chennai (since I have never have had an H1B visa, I can not request for expedition/emergency).
>>> Usually the appointment slots opens only 2-3 weeks in advance.

[JMK]

Thank you.