I agree with Dave - a database is likely the better approach. Nick Hodge
explains how to use parameter queries to pull data from Access

http://www.nickhodge.co.uk/gui/datam...taexamples.htm

but the advice works equally well with SQL Server (or even an Excel
worksheet set up as a database).

I'd use Nick's advice in conjunction with a test for the number of rows that
are returned for a given surname. If more than one row is returned, you can
populate a list box on a popup form and let the user choose the correct data.