If you have a good limit on DCB (> 8 lakhs) and a good spend history in the past few months, mail their credit card grievance email id and ask for an upgrade. HDFC does give generous LE (annually/ semi-annually) if your spends are good.
I got DCB FYF after using Regalia for over 6 years (automatically through NetBanking), but acceptance was a serious issue. Mailed them about this and got upgraded to Infinia in less than 2 months after getting DCB. My limit on Regalia itself was very good though and I spent 1.5L+ on DCB in less than 2 months before asking for the upgrade.
I got DCB FYF after using Regalia for over 6 years (automatically through NetBanking), but acceptance was a serious issue. Mailed them about this and got upgraded to Infinia in less than 2 months after getting DCB. My limit on Regalia itself was very good though and I spent 1.5L+ on DCB in less than 2 months before asking for the upgrade.