On Error Resume Next
CurrentDb.Execute "INSERT INTO Table1 (Fields) VALUES (Data)", dbFailOnError
If Err.Number = 3022 Then
Err.Clear
CurrentDb.Execute "UPDATE Table1 SET (Fields = Values) WHERE Column1 = 'SomeValue'", dbFailOnError
ElseIf Err.Number <> 0 Then
'Handle the error here
Err.Clear
End If