VBA to import Excel worksheet, append new rows, and update existing rows

Question

I'm using Excel to produce reports for a support ticketing system, and I'd like to use VBA to simplify the process of updating the report data. What I want to do is import an Excel file dumped from the ticketing system into the Excel file I'm using for reporting, but with a twist. I need to use the value in one column to identify whether the ticket is new or existing. If it's new, I want to add it to the reporting file. If it's existing, I want to overwrite the matching row (based on the matching column value, which is the ticket number) with the imported data. So the basic process would be:

1. Open exported file (I know how to do this)
2. For each row in exported file
3. Read ticket number (column A)
4. Search existing sheet column for ticket number (also column A)
5. If found then replace information with imported data (columns B-X)
6. Else append imported data as a new row (columns A-X)
7. Next row

Steps 4-6 above are what I'd like help with. I can use a formula such as =NOT(ISNA(MATCH([imported ticket ID],[array of existing ticket IDs],0))) to return TRUE if the ticket ID exists and FALSE if it doesn't, but would like to find a more elegant solution if one exists.

Does anyone here have experience with doing this and/or some VBA code I might be able to tweak to suit my purposes? Thanks in advance.

EDIT: Here is the code I have so far. It's not much.

Sub UpdateTickets()
'Specify data export file
Dim fNameAndPath As Variant
fNameAndPath = Application.GetOpenFilename(Title:="Select File To Be Processed")
If fNameAndPath = False Then Exit Sub
'Open data export file
Workbooks.Open Filename:=fNameAndPath
'For each row in data export file, starting at Row 2
'Check master data file (column A) for ticket number
'If ticket number exists, update information in columns B through P
'Else add new ticket row and place information in columns A through P
'Next row
End Sub

Answer 1

I just wrote this, and it worked:

    Sub import_tickets()
        'run this when the active file is the main ticket list and the active sheet is the ticket list
        'exported file must be open already, and the ticket list must be the active sheet
        Dim exported_file As String
        exported_file = "exported file.xlsx"
        header_exists = True 'if exported file doesn't have a header, set this to false!
        starting_row = 1
        If header_exists Then starting_row = 2

        Dim first_blank_row As Long
        first_blank_row = Cells.SpecialCells(xlCellTypeLastCell).Offset(1, 0).Row

        Dim r As Long
        r = starting_row
        Dim found As Range
        cur_ticket_num = Workbooks(exported_file).ActiveSheet.Range("a" & r).Value
        Do While Not cur_ticket_num = ""
            'look for current ticket number in main file
            Set found = Columns("a:a").Find(what:=cur_ticket_num, LookIn:=xlValues, lookat:=xlWhole)
            If found Is Nothing Then
                'add info to end of main file
                write_line_from_export exported_file, r, first_blank_row
                first_blank_row = first_blank_row + 1
            Else
                'overwrite existing line of main file
                write_line_from_export exported_file, r, found.Row
            End If
            r = r + 1
            cur_ticket_num = Workbooks(exported_file).ActiveSheet.Range("a" & r).Value
        Loop
    End Sub

    Sub write_line_from_export(src_filename As String, src_r As Long, dest_r As Long)
        For c = 1 To 24
            Cells(dest_r, c).Value = Workbooks(src_filename).ActiveSheet.Cells(src_r, c).Value
        Next c
    End Sub

I hope it helps. I referenced this page for the first blank row code and this page for the find code. I wrote the code in the main ticket file's module.