In the event of an extension to the duration of the training period provided for in 2° or 3° of article R. 426-16, an amendment to the training agreement is sent to the prefect using a teleservice, within the meaning of article L. 112-9 of the Code of relations between the public and the administration, or by registered letter with acknowledgement of receipt at least fifteen days before the end date of the training period initially planned by the training organisation or host company. If the prefect remains silent for fifteen days, this constitutes a decision to accept.