Message Box Display of Variable From a Different Sub

[gmaxey]

I don't really understand what you are trying to do or the purpose of Sub Data1() or Sub Data(2), but you could use a module level variable:

Option Explicit
Private m_TextToDisplay As String
Private Sub BtnClick()
  If ComboBox.Value = "Data 1" Then
    Data1
  ElseIf ComboBox.Value = "Data 2" Then
    Data2
  End If
End Sub
Private Sub Data1()
  m_TextToDisplay = "Lorem ipsum dolor sit amet, consectetur adipiscing elit."
End Sub
Private Sub Data2()
  m_TextToDisplay = "Curabitur eu est libero."
End Sub