There is no option or function to automatically merge one Vendor's transactions and information into another existing Vendor's file.

What you can do, however (after making a good backup of your qc datafiles) is to manually edit the Vendor Statistics of the Vendor you wish to keep active to reflect the new YTD information as it would be if you added the duplicate Vendors' stats together. Once you are happy that the figures are correct, you can then delete the duplicate Vendors from QCWIN.

To be able to search by other criteria besides the Vendor Name, you can press <F6> to access the detailed Finder. You can also change the columns displayed in this finder to allow for your specific needs by double-clicking on one of the column headings to access the QCWIN Column Editor.

Hope this helps!