Conditional Formatting on Variable range

[Paraboot]

Good morning,

I am trying to make a VBA code to check if the out time has been filled in if there was an in time. If the out time has been left blank the 2 cells need to become yellow when afterwards the cell gets filled in by the user the color needs to disappear. Therefor I am trying to use Conditional formatting in my VBA code but I can't seem to get it working.
this is the code I use so far:

Set v_laatstecel = [b65536].End(xlUp)
    Set v_gebied = Range([b5], v_laatstecel)
    For Each v_cel In v_gebied
        Set v_in = v_cel.Offset(0, 6) 'in times
        Set v_uit = v_cel.Offset(0, 7) 'out times
        If IsEmpty(v_in) Then
           
        Else
            If IsEmpty(v_uit) Then
                v_uur = v_in.Value
                v_in = v_date - 1 & " " & v_uur
                v_rij = v_cel.Row
                Range(v_in, v_uit).FormatConditions.Add Type:=xlExpression, Formula1:="=ISBLANK(" & v_uit & ")"
                With Selection.FormatConditions(1)
                    .Interior.Color = 36
                    .StopIfTrue = True
                End With

could anybody help with this?