Exception handling for Save As in Excel VBA

The below segment of code works fine, but if the file already exists, it asks if you want to overwrite or not. If I say yes, it works fine. If I say no, it gives the error, "Method save as object_workbook failed". What can I do to handle this exception?

    ActiveWorkbook.SaveAs fileName:= _
       "J:\Reports\WeeklySafeLink\" & stYear & "\" & stYear & stMonth & "\" & stYear & stMonth & stDay & "\" & "TracFone Commission.xlsx", _
       FileFormat:=xlOpenXMLWorkbook, CreateBackup:=False