Hi Varsha
You can use the same command to update date and time; AT+CCLK="yy/mm/dd,hh:mm:ss+zz". Here yy=year(last 2 digits), mm=month, dd=date, hh=hours, mm=minutes, ss=seconds and zz=deviation from GMT in 15 min. intervals i.e for india if IST=GMT+5:30 then zz=22.
A successful response would be "OK".
This should work