Send the below email. You would get it
"I have an existing  Indusind Bank [ card name ] Credit Card with last 4 digits 0000. Can you please help to upgrade this card 0000 to an Indusind Tiger Credit Card?  Please treat the requirement as important. My cell number is 0000000000"
Cc: 
Prateekm@bajajcapital.com
To: 
Priority.care@indusind.com
I am currently in process of doing it.