VBA: loop through data in column A if exists then paste new row over existing, if it does not exist then paste at bottom of rows : Sheet 1 holds data columns A:L and needs existing rows updated and new rows added at bottom.

Sheet 2 gets updates of only new data or changed data and is formatted the same as sheet 1. it gets cleared after sheet 1 is updated.

In column A is a work order number. 

I need a code to run in sheet 2, that updates sheet a 1 based on the following criteria.

Loop though sheet 1 column A, if value in column A already exists update that row with new data, if value in column A does not exist paste row at bottom of sheet 1