Deleting controls is the same as "deleting" (called closing in programming terminology) an App.
Add the following to a Form with 2 CommandButtons called Command1 and Command2. When you press Command2, it will close (delete) Command1.
Code:
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Private Declare Function DestroyWindow Lib "user32" (ByVal hwnd As Long) As Long
Private Const WM_CLOSE = &H10
Private Sub Command2_Click()
SendMessage Command1.hwnd, WM_CLOSE, 0, 0
DestroyWindow Command1.hwnd
End Sub