IF Cell Falls Within A Specific Range Then

I am half way through a Worksheet where I am using VBA to perform more than the measly 3 Conditional formats that excel offer. This is working fine but I am now looking into a way of reversing the formats if a mistake is made and the condition is removed.

To make this sound more straightforward it is a rota sheet. If I enter Holiday the cells interior turns pink, Half turns light blue, On Call turns green etc. If this is changed I need to change it back to the original formatting.

I have partly done this with a Case "" but the Rota changes colour with different teams so I need to have an IF statement in there that say if the Target Cell falls within this Range say A5:AF10 change to tan IF the target falls within A6:Af20 change to sky blue etc. Below is the code I have so far.

Private Sub Worksheet_Change(ByVal Target As Excel.Range)
Dim WatchRange As Range
Dim CellVal As String
On Error Resume Next
CellVal = Target
Set WatchRange = Range("A1:AF100")
If Not Intersect(Target, WatchRange) Is Nothing Then

Select Case CellVal
Case "Holiday"
Target.FormatConditions.Delete
Target.Interior.ColorIndex = 38
Target.Font.ColorIndex = 1......................