17.1 The Authorities may vary the terms of this Agreement including admitting additional Authorities to the Joint Committee, the terms of such admission to be agreed by the Authorities.
17.2 Where an additional Authority is admitted to the Joint Committee it shall enter a Deed of Variation in a form agreed by the Joint Committee and from the date of its admittance to the Joint Committee all provisions of this Agreement shall apply to the admitted Authority and the definition of "Authorities" shall include it.