Column Match function to replace

Hello,

I have 2 sheets
1st SH - User uses List validation to choose from column headers in 2nd sheet
after choice made, vlookup function brings info under column header to sheet
1.

I want user to be able to alter the info came over with event macro (vlookup
/ copy / pastes ) and update the column in SH2.

cell Z1 contains match formula to match up header to proper column in SH 2.
How can i build code to use the matched column to properly overide the
existing data with altered.

My problem isn't with the middle part (copy / pasting) but just how to
define that matched value as the proper column to override.

Hope makes sense... your help most appreciated.

Steve