Hello Anu
This will give it to you provided that ticket number and date are both in ascending order. Enter in B2 and you can copy across. Obviously the ranges will have to be set to suit your real data.
=MAX((Sheet2!$A2=Sheet1!$A$2:$A$4)*Sheet1!B$2:B$4) Enter with Ctrl/Shift/Enter (Array formula)
Otherwise, you might have to use MATCH and OFFSET to get the appropriate date in C2.
=OFFSET(Sheet1!$C$1,MATCH(B2,Sheet1!B$2:B$4,0),0)
Hopefully this should get you on the right track.
Harry