copy column in WB1 and paste it in specified columns in WB2

hi,

i have 2 WB's
WB1 --> sheets 1(update1)-->columns(first name, middle name, last name, address, address1...)
WB2 -->8sheets(with specific names) -->columns(varies but might have same column name as in WB1 or might not have)

issue: need to copy a column from WB1 say first name, paste it in all relavent sheets with column name "first name"
again search for last name and paste in WB2 on relavent sheets and in relavent column name,

i have coded a bit here but it does in same workbook but not in different work book. please have a look

Option Explicit
'Function to check if worksheets entered in input boxes exist
Public Function wsExists(ByVal WorksheetName As String) As Boolean

On Error Resume Next
wsExists = (Sheets(WorksheetName).Name <> "")
On Error GoTo 0 ' now it will error on further errors

End Function

Sub copy_using_header()

Dim i As Integer
Dim a(1 To 1) As Integer
Dim b(1 To 1) As Integer
Dim lkup As String
Dim dummy As Variant
Dim Sheet_Copy_From As String
Dim Sheet_Copy_To As String
Dim sn As Variant 'sheet name from array to test
Dim an As Variant 'Array
Dim lkr As range
Dim ahd As Variant
Dim chd As Variant
Dim cn As Long
Dim ws As Worksheet
Dim lkr1 As range
Dim ahd1 As Variant
Dim chd1 As Variant
Dim cn1 As Long
Dim ws1 As Worksheet


Application.ScreenUpdating = False 

Sheet_Copy_From = Application.InputBox(Prompt:= _
        "Please enter the sheet name you which to copy from", _
        Title:="Sheet_Copy_From", Type:=2) 'Type:=2 = text
    If Sheet_Copy_From = "False" Then 
    Exit Sub
    End If
     
Sheet_Copy_To = Application.InputBox(Prompt:= _
        "Please enter the sheet name you which to paste in", _
        Title:="Sheet_Copy_To", Type:=2) 'Type:=2 = text
    If Sheet_Copy_To = "False" Then 
    Exit Sub
    End If
    
    
  an = Array(Sheet_Copy_From, Sheet_Copy_To)
  
  For Each sn In an
    
    Select Case wsExists(sn)
    Case False
      MsgBox "The worksheet named ....""" & sn & """ .... is either missing" & vbNewLine & _
            "or spelt incorrectly" & vbNewLine & vbNewLine & _
            "Please rectify and then run this procedure again" & vbNewLine & vbNewLine & _
            "Select OK to exit", _
            vbInformation, ""
            
      Exit Sub
    End Select
 Next

For i = 1 To 1

Select Case i
    Case 1
    lkup = Application.InputBox(Prompt:= _
        "Please enter column heading name", _
        Title:="InputBox Method", Type:=2) 
End Select
If lkup = "False" Then 
    Exit Sub
    End If

On Error Resume Next 

    a(i) = Sheets(Sheet_Copy_From).Rows(1).Find(lkup, LookIn:=xlValues, LookAt:=xlWhole, MatchCase:=False).Column
    b(i) = Sheets(Sheet_Copy_To).Rows(1).Find(lkup, LookIn:=xlValues, LookAt:=xlWhole, MatchCase:=False).Column


     Sheets(Sheet_Copy_From).Select
     range(Cells(2, a(i)), Cells(Cells(Rows.Count, a(i)).End(xlUp).Row, a(i))).Copy ' Only copies from row 2
       
        
    Sheets(Sheet_Copy_To).Activate
        With Cells(2, b(i)) ' Pastes from row 2 down
          .PasteSpecial Paste:=xlPasteValues
        End With
        
    Application.CutCopyMode = False 
 Next 
On Error GoTo 0         
    Set dummy = Worksheets(1).Cells.Find(What:=" ", after:=ActiveCell, LookIn:=xlFormulas, _
    LookAt:=xlPart, SearchOrder:=xlByRows, SearchDirection:=xlNext, MatchCase:=False)    
    Application.ScreenUpdating = True  
End Sub