Change Value In Workbook from Outlook Macro

[Benzula]

So I have a Macro that Opens an Attachment, and saves it in a shared drive location. After it saves I need to change the value of A1 to "Hostname"

Set objApp = CreateObject("Excel.Application")


            objApp.Visible = False
            Set wb = objApp.Workbooks.Open("\\ServerName\ShareName\Incubator\AutoEmails\FileName.xlsx", True, False)


            'Change Value in A1 of Servers Tab
            wb.Worksheets("Servers").Range("A1").Value = "Hostname"
            
           activeworkbook.Save
           activeworkbook.Close
           Application.Quit
          
End Sub

Also I'd prefer it if I could save/close it by Name like wb(UnixSystemAssignements).Save & Close