Private Sub btn_Ok_Click()
    Dim s As String
    s = Application.CurrentProject.BaseConnectionString
    Debug.Print "Было "+s
    CurrentProject.CloseConnection
    CurrentProject.OpenConnection s, user, pas
     ''CurrentProject.Connection.Properties.Item("Application Name") = "hhh" 
    s = Application.CurrentProject.BaseConnectionString
    Debug.Print "Стало "+s
End Sub

Было PROVIDER=SQLOLEDB. 1 ;PASSWORD=xxx;PERSIST SECURITY INFO=TRUE;USER ID=sa;INITIAL CATALOG=arch2000_convSQL;DATA SOURCE=smeta-server;Use Procedure for Prepare= 1 ;Auto Translate=True;Packet Size= 4096 ;Application Name=erwgteryh;Workstation ID=SMETA-SERVER

Стало PROVIDER=SQLOLEDB. 1 ;PASSWORD=xxx;PERSIST SECURITY INFO=TRUE;USER ID=sa;INITIAL CATALOG=arch2000_convSQL;DATA SOURCE=smeta-server