Sub test()

    Dim rExp As Object, TheMatches As Object, MyStr
    MyStr = ActiveDocument.Range.Text

    Set rExp = CreateObject("VBScript.RegExp")

    With rExp
        .Pattern = "^([^\n]*?)(- )$"

        .IgnoreCase = True
        .Global = True
        .MultiLine = True
        Set TheMatches = .Execute(MyStr)                'Just to check
        MyStr = .Replace(MyStr, "START$2$1END")

    End With

    Debug.Print (MyStr)                         'check the debug for the results

End Sub

'sample text, put the following 3 lines in an empty document

'00:03:43,146 --> 00:03:47,413
'Where?-                    'this is supposed to become "-Where?"
'At home.-                  "-At home."