VBA to allow date change in a cell, but not deletion of cell value.

I am trying to only allow date modification in cell G19. Currently I have Data Validation on the cell which only allows date formats. However a user can delete the date, which prompts the user to enter a date, after the deletion, has occurred. I would prefer to have a error message pop up, prior to the deletion. I cannot protect the sheet, because it causes problems with other cells. Is it possible to just allow date modification?

Validation is working fine. I do have an active input message. However a certain user has a history of ignoring the warnings, I am trying to have a warning come up prior to the deletion. or possibly some code that would UNDO the deletion after the change event. BUT only a deletion.

The code does prevent deletion, but does not allow modification. I.E. from 10/1/2000 to 10/1/2019. Also would it be possible to include an error message, when a deletion is attempted?

Thanks. At least I now know want I want is not possible.

Thank You, for working out a solution. it is what I was looking for.

Something weird is happening. Your test sample works as expected. However when I run it in my file, I get the following error message: "Cannot run the macro"file location& name!. The macro may not be available in this workbook or all macros may be disabled." This is a macro enabled workbook, & the other macros work. Below is a listing of the code on the sheet in question.
[VBA]
Option Explicit
'Public Sub AllowMacros()
'This allows a macro to run & keep the sheet protected.
'Me.Protect UserInterfaceOnly:=True
'End Sub
Private Sub Worksheet_Change(ByVal Target As Range)
'This section of code clears the second listing of a duplicate, & allows the first.
Dim r As Long
If Not Intersect(Range("B5:B17,H4:H16"), Target) Is Nothing Then
Application.EnableEvents = False
For r = 5 To 17
If Range("H" & r - 1).Value = "No" And Range("B" & r).Value <> "" Then
Range("B" & r).ClearContents
End If
Next r
Application.EnableEvents = True
End If

'This section of code provides notification if there is a scheduling conflict.
If Target.Count > 1 Then Exit Sub
If Not Intersect(Target, Range("H5:H10, H13:H17")) Is Nothing Then
If LCase(Target.Value) = LCase("No") Then
MsgBox "If there is pink in a previously filled cell, after checking No." & vbCrLf & _
"There is Scheduling conflict." & vbCrLf & _
"Choose another time or reschedule the first veteran" & vbCrLf & _
"Remember! New Career Link Visits require 1 hour.", vbCritical, "Vocational Services - OVR " & ActiveSheet.Name
End If

End If
'This code prevents modification or deletion of cells in the range below. You do not need to protect the sheet.
If Intersect(Target, Range("A3:P3,B11:P12,B33:L50,B59:B60,C32:J32,D4:D17,E20:F21,F59:N60,G20:G22,H18:I18")) Is Nothing Then Exit Sub
On Error GoTo ExitPoint
Application.EnableEvents = False
If Not IsDate(Target(1)) Then
Application.Undo
MsgBox " You can't delete or modify cell contents in this range " _
, vbCritical, "Vocational Services - OVR " & ActiveSheet.Name
End If
ExitPoint:
Application.EnableEvents = True

End Sub

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Target.Address = "$G$19" Then
Application.OnKey "{DEL}", "Warning"
Application.OnKey "{BACKSPACE}", "Warning"
Application.OnKey " ", "Warning"
Else
Application.OnKey "{DEL}"
Application.OnKey "{BACKSPACE}"
Application.OnKey " "
End If
End Sub
[/VBA]
I can't see anything wrong. Is there something I am missing?

I am SOOOOOOOOOOO sorry. I forgot to add this to the module:
[VBA]Private Sub Warning()
MsgBox " You can Edit the Date ...or..." & vbNewLine _
& vbNewLine & " You can Type a New Date on top of the existing one ... " & vbNewLine _
& vbNewLine & " BUT you cannot Delete the cell's content ....!!!"
End Sub
[/VBA]
It works fine. Apparently it is too early for me to think.

I added this piece of code to get rid of the Microsoft title in the window.[VBA], vbInformation, "Vocational Services - OVR " & ActiveSheet.Name[/VBA]
Again Thank You