send email along with dcb pic (details hidden) and latest dcb statement attached, to
banker@idfcfirstbank.com
you may also attach your salary slips or itr if it is high.
rest completely depends on their team. they have no formal upgrade process and retention teams.
i once threatened them to close wealth card and they said go ahead.
select is a useless card now if you have dcb, so no problem in going ahead and closing it and wait for 6 months before reapply for wealth.