need to modify user defined function macro

Option Explicit

Function SortConcat(Rng As Range) As Variant
    'Rng —The range of data to be sorted and concatenated.
    Dim MySum As String, arr1() As String
    Dim j As Integer, i As Integer
    Dim cl As Range
    Dim concat As Variant
    On Error GoTo FuncFail:
    'initialize output
    SortConcat = 0#
    'avoid user issues
    If Rng.Count = 0 Then Exit Function
    'get range into variant variable holding array
    ReDim arr1(1 To Rng.Count)
    'fill array
    i = 1
    For Each cl In Rng
        arr1(i) = cl.Value
        i = i + 1
    Next
    'sort array elements
    Call BubbleSort(arr1)
    'create string from array elements
    For j = UBound(arr1) To 1 Step -1
        If Not IsEmpty(arr1(j)) Then
            MySum = arr1(j) & "," & MySum
        End If
    Next j
    'assign value to function
    SortConcat = Left(MySum, Len(MySum) - 2)
    'exit point
concat_exit:
    Exit Function
    'display error in cell
FuncFail:
    SortConcat = Err.Number & "-" & Err.Description
    Resume concat_exit
End Function

Sub BubbleSort(List() As String)
' Sorts the List array in ascending order
    Dim First As Integer, Last As Integer
    Dim i As Integer, j As Integer
    Dim Temp
    
    First = LBound(List)
    Last = UBound(List)
    For i = First To Last - 1
        For j = i + 1 To Last
            If UCase(List(i)) > UCase(List(j)) Then
                Temp = List(j)
                List(j) = List(i)
                List(i) = Temp
            End If
        Next j
    Next i
End Sub