Depending on the settings, you may be able to edit or add the diagnosis on the consultation page after the consultation invoice has been finalised.
To edit a diagnosis on the consultation page, select the pen button at the end of the diagnosis row.
To delete a diagnosis, select the pen button at the end of the diagnosis row and then select Delete in the dialogue.
If editing is not allowed, you can add a new diagnosis on the patient page and link it to the relevant consultation.