Call Private Sub Worksheet_Change

Put your code in a separate subroutine. Call that subroutine from both the worksheet change event, and from Macro 1.

e.g.

Private Sub Worksheet_Change(ByVal Target As Range)
    Call foo
End Sub

Sub foo()
    'your code here
    Debug.Print "foo happened"
End Sub

Sub Macro1()
    Call foo
End Sub