Append data in a Textbox after a checkbox is checked

[Summit_IT]

This code works, but I want it to append existing data in a textbox not just replace.

Private Sub PartNeeded_AfterUpdate()
'This will append the CorrectiveAction textbox with a statement when the PartNeeded checkbox is checked'
If Me.PartNeeded = True Then Me.txtCorrectiveAction.Value = "Inspected in accordance with manufacturer's maintenance manuals and was found defective. Part was replaced with a serviceable part."
If Me.PartNeeded = False Then Me.txtCorrectiveAction.Value = Null
End Sub

I have six checkboxes I want to use to append this one textbox.
Also, I want manually entered data to stay in this textbox. This data must also be manually removed if user makes a mistake.

[Welshgasman]

Me.txtCorrectiveAction = Me.txtCorrectiveAction & " " & "Inspected in accordance with manufacturer's maintenance manuals and was found defective. Part was replaced with a serviceable part."

Why two If statements?, use an Else instead.

[Micron]

maybe use the syntax of
If Me.PartNeeded = True Then Me.txtCorrectiveAction = Me.txtCorrectiveAction & " Inspected in accordance with ...
Not the injection of a space before the addition. If you want a line feed, concatenate vbCrLf instead of a space.
Please use proper indentation with code.
Thanks.

Too late.