In step 3, the system edits the information. However, in extension 3a, the system shows an error message and prompts the user to use a different command (implied - does not edit the information). Not editing the information (3a) cannot happen after editing the information (3), so the number should not be 3a.
In step 3, the system edits the information. However, in extension 3a, the system shows an error message and prompts the user to use a different command (implied - does not edit the information). Not editing the information (3a) cannot happen after editing the information (3), so the number should not be 3a.