Forms :: Use Buttons On A Form To Change Sort Order On A Continuous Form

I want to use buttons on a form to change the sort order on a continuous form. In the buttons click event I am using a public function (named Sort_1) to change the sort order. The first element of the event call is the name of a generic query (named Sort_1_Query1) and the query field to sort (LAST_NAME OR FRIST_NAME, depending on the button.)This is the Click Statement.

=Sort_1("Sort_1_Query1","LAST_NAME")

This is the Public Function
Public Function Sort_1(SortName As String, FieldName1 As String)
DoCmd.ApplyFilter SortName, FieldName1 & "between 'A' and 'Z'"
End Function

I think the problem is in the use of quotation marks or trying to pass the query field name to the Do Command or the use of an ampersand.