Search for text in multiple columns with same heading - excel Macro

Hi Team,

I am very new to excel macros. I tried to write a macro for one of our requirements.

The macro renames the department based on the list of managers corresponding to that department.
It should search for a manager name in the columns H to Q and accordingly rename the department. But it is searching only column H. Please help me out. The macro text for your reference.

Sub DepartmentList()
   'ASSIGN DEPARTMENTS BASED ON MANAGER 
    Dim intDepartmentColumn As Integer
    Rows("1:1").Select
    intDepartmentColumn = Selection.Find(what:="Department", After:=ActiveCell, LookIn:=xlFormulas, LookAt:=xlPart, SearchOrder:=xlByRows, SearchDirection:=xlNext, MatchCase:=False, SearchFormat:=False).Column
    Rows("1:1").Select
    Selection.Find(what:="Manager", After:=ActiveCell, LookIn:=xlFormulas, LookAt:=xlPart, SearchOrder:=xlByRows, SearchDirection:=xlNext, MatchCase:=False, SearchFormat:=False).Select
    Selection.Offset(1, 0).Select
    Range(ActiveCell, Cells(ActiveSheet.UsedRange.Rows.Count, 17)).Select
    For Each cell In Selection.Cells
         Select Case cell.Value
            Case "Thuan Tran", "Deborah Donoghue", "Edmond Albert Navarro", "Christopher Arndt-Kohlway", "Chris Arndt-Kohlway", "Efren Saraza", "Rajesh Raghavendran", "Troy Rudy", "Colin Fraser", "Timothy Gleadle"
                Cells(cell.Row, intDepartmentColumn) = "IT Operations"

            Case "Daniel Singleton", "Paul Brockman", "Stuart Johnston", "Darren Walton"
                Cells(cell.Row, intDepartmentColumn) = "IS End User Computing"

            Case "John Goodreau", "Timothy Westcott", "Krishnan Balasubramanian", "Asheesh Chhabra", "Eric Keller", "Michael Galiardi", "Michel Roberge", "Mathew Griffin"
                Cells(cell.Row, intDepartmentColumn) = "SDD"

            Case "Jeffrey Kase"
                Cells(cell.Row, intDepartmentColumn) = "Information Assurance"

            Case "Venkatesh Appiya", "Anup Samantaray", "Lisa Rosenfeld"
                Cells(cell.Row, intDepartmentColumn) = "Program Management"

            Case "Kavitha Ravella"
                Cells(cell.Row, intDepartmentColumn) = "ITSM"

            Case "Jennifer Carr", "Dale Todd"
                Cells(cell.Row, intDepartmentColumn) = "ITCM"

            Case Else
                Cells(cell.Row, intDepartmentColumn) = "MISC"

        End Select
    Next
End Sub

The format of excel sheet is as follows. (headings)

Number Short description Opened by Change Owner Department This Change Request is Unauthorized Reason Manager Manager Manager Manager Manager Manager Manager Manager Manager Manager