The report's Detail Format event can do this.  This event runs right before each record is printed.  In the event, write VBA code that checks if the notes field of the current record is empty not, then hide or unhide the label accordingly.

Kevin is right that you can handle it with a little VBA in the Detail section's Format event. However, there's a good chance you don't need any programming at all.

Set both the Notes field itself and the section it is in to CanShrink = Yes. You also have to make sure there is nothing beside the Notes field, including its label, because labels can't shrink. If the label is next to the field, it can prevent the empty space from collapsing.

I cover all of that in this video:

Can Grow, Shrink

I have watched the video Can Grow, Can Shrink and I guess I must not fully understand the label and text box must be attached. I have tried multiple times to get this to work. I have checked the VBA code, it looks fine. Just can't get the label Notes to re-appear when needed. I am sure it's something simple that I have overlooked.

One other thing you can try to hide the label itself is to use a conditional statement (if then or select case) to set the ".visible" to false.  May not help with the can shrink property, but it will hide the label on records with no notes.  See example from one of my forms below.  Hope it helps:
    '[20260223-DAN]-Records cleanup, only show legacy records if they still exist
    If Not IsNull(NotesText) Then
        NotesText.Visible = True
        NotesLabel.Visible = True
    Else
        NotesText.Visible = False
        NotesLabel.Visible = False
    End If

I would code it like this:

    If Nz(NotesText, "") = "" Then
        NotesLabel.Visible = False
    Else
        NotesLabel.Visible = True
    End If

If Can Grow / Can Shrink is set to Yes, you shouldn't need to control the visibility of NotesText.

The important part is that you have to explicitly turn the label back on in the Else. The Format event runs once for every record. If one record hides the label and the next record has notes, the label will stay hidden unless you set it back to True.

Also make sure NotesLabel is the actual Name property of the label control, not just the caption that says "Notes.

By George, I think I've got it!
Thank to all!

Hi David, Maybe By Kevin and by Richard, I think I've got it! John