This is what's mentioned at the end of my email.
In the event you wish to proceed with this upgrade process, we request you to share the below consent from your registered email ID.
1. Your consent for card upgrade mentioning the last four digits of your current card number.
2. Credit Card variant to be upgraded.
3. Acceptance towards annual membership fee (As mentioned in Upgrade form).
4. Acceptance towards transfer of Reward points (if any) from your old HDFC Bank credit card to the new card variant as per the applicable conversion ratio (Refer 2nd page of Upgrade form for details).
5. Acceptance to scrutinize Credit Bureau reports such as CIBIL, Equifax etc. to review eligibility as per credit policies.
Alternatively, you may also revert back to us with scanned copy of upgrade form(URL mentioned below) duly filled and signed to enable us review your request.
Upgrade form URL : Please visit
https://www.hdfcbank.com/personal/resources/forms-centre/forms-center-personal ->Select "Credit cards" -> View Upgrade form with name "Application for Limit Increase or Credit Card Upgrade - For Customer".