convert all xlsx in directory to text using vb

I am trying to convert each xlsx to a txt in the directory without deleting the original, but the syntax is not correct. Thank you .

VB

Private Sub CommandButton1_Click()
    ChDir "C:\Users\cmccabe\Desktop\epilepsy"
    ActiveWorkbook.SaveAs Filename:= _
        "C:\Users\cmccabe\Desktop\epilepsy\*.xlsx", _
        FileFormat:=xlText, CreateBackup:=False
End Sub

The second VB runs but no output results.