Convert DD-MM-YY to DD-MM-YYYY using sub/function - vba

Question

I have been given a list of enrollment dates for some sources for an assignment.
They want me to change the dates using vba
The question is:
"As with the previous assignment that the Director gave you, the enrollment date is in a “not normal” format. The director wants the date changed into the “normal” Danish format “DD-MM-YYYY”. You, therefore, must create a sub/function that changes the date in the field to the “correct” format. As the function needs to be able to run multiple times you should use the appropriate selection statements to check that the date is in the “not normal” format before converting it."
I have attached a picture of the excel

Answer 1

This function appends a 20 before the year part if its only 2 characters.
Function DateConvert(BtVal dt As String) As String
Dim parts As String()
parts = Split(dt, "-")
dd = parts(1)
mm = parts(2)
yy = parts(3)
DateConvert = dd & "-" & mm & "-" & IIf (Len(yy) = 2, "20" & yy, yy)
End Function
You might want to extend this logic, for example "65" can be replaced with "1965" instead of "2065", but I leave that part to you.

Answer 2

The function will test whether the string matches the pattern. If it does, it returns formatted date, otherwise it returns same cell's value.
Function GetDate(cell)
With CreateObject("VBScript.RegExp")
.Pattern = "^(\d{2})-(\d{2})-(\d{2})$"
With .Execute(cell)
If .Count > 0 Then
With .Item(0)
GetDate = Format(DateSerial(.SubMatches(2), .SubMatches(1), .SubMatches(0)), "dd-MM-yyyy")
End With
Else
GetDate = cell
End If
End With
End With
End Function