Locate Values And Add Text In The Same Row

I have created a form that will be used my many people. The first person will enter their information and click a button to transfer their data to a second workbook, as well as send the workbook via email. At a later time, someone else will add more data to the emailed form and transfer this to the database in the second workbook. What I need is to be able to find the row in the second workbook containing the data transferred the first time and add the data that was put in later to the same row as the original.