how to transpose a large data from columns into rows
 

I have a large data file, it has all monthly data by columns with some SKU,
Sales Pirce, sales unit measurement. How to transpose the monthly data into
rows, because I need to combine it with another file, which all monthly data
is by rows, but the firlst three columns are same (Item, Price, UOM).

For example,
Item Price UOM Jan Feb Mar
A - 1 12.35 Lb 53,500 55,000 50,000
A - 2 7.56 Lb 3,000 4,000 3,500
A - 3 9.2 Lb 19,800 19,800 19,800
A - 4 15.93 Lb 67,485 71,445 79,365