Public Class Form1
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        Dim n As New List(Of String)

        n.Add("test0")

        pAlterList(n)

        Debug.Assert(n(0) = "test0")

    End Sub

    Private Sub pAlterList(ByVal u As List(Of String))

        u(0) = u(0) & "somechange"

    End Sub

End Class