update or amend worksheet

ok have a work sheet and userform which is populated from worksheet
this is the code i use to populate text boxes

Option Explicit
Dim cl         As Range

Private Sub CommandButton1_Click()
    'get the next line of data
    Set cl = ActiveCell.Offset(1, 0)
    'switch off ScreenUpdating to speed up code & prevent flickering
    Application.ScreenUpdating = False
    cl.Select
    'if there is no more data then notify the user & quit
    If cl.Value = "" Then
        TextBox1.Value = "No more Data"
        TextBox2.Value = ""
        Exit Sub
    Else
        'load UserForm with fresh data
        TextBox1.Value = cl.Value
        TextBox2.Value = cl.Offset(0, 1).Value
        TextBox3.Value = cl.Offset(0, 2).Value
        TextBox4.Value = cl.Offset(0, 3).Value
    End If
    'restore ScreenUpdating
    Application.ScreenUpdating = True
End Sub

Private Sub CommandButton2_Click()
Unload Me
End Sub

Private Sub UserForm_Initialize()
    'select the first cell in the column of data
    Set cl = Cells(2, 1)
    cl.Select
    'enter the required data into the textBoxes
    TextBox1.Value = cl.Value
    TextBox2.Value = cl.Offset(0, 1).Value
    TextBox3.Value = cl.Offset(0, 2).Value
    TextBox4.Value = cl.Offset(0, 3).Value
End Sub

how can i use this to also update if i change any data in the text boxes if you see what i mean
cheers
Doug