In an active sheet, I have col headers in row1, data from row2 down.
I need to carve out uniques based on the "Order ID" col header, and
paste these unique lines into a new sheet, then name this new sheet as:
UniqueOrderIDs

How could the above functionality be done by a sub? There will be only one
col header: Order ID within row1. But its position may vary from day-to-day,
hence the sub needs to locate the col via the header text, then do the
necessary

Manually, I extract like this
Assuming the col header: Order ID is in R1
Using a empty col to the right, in say, AF2:
=IF(R2="","",IF(COUNTIF($R$2:R2,R2)1,"","x"))
AR2 is then copied down to last row of data in col B (Col B is always used
to determine data extent here). Then I'd apply autofilter on col AF for "x",
copy the entire sheet (with the filtered results) n paste it into a new
sheet, then rename the sheet as: UniqueOrderIDs