Any modification of this agreement between the parties is filed jointly by the parties within thirty (30) days from the date of conclusion of the contract with the clerk of the labor court: PROVIDED that the modification agreement takes effect only when the labor court has become aware of it. Any such amendment agreement, of which the Labour Court has become aware, shall be binding on the parties from the date and period fixed therein, but such period may not begin before the date of entry into force of this Agreement. Either party may terminate the remaining six (6) months in writing with proposals to negotiate a new agreement, but such notification may not be made before July 1, 2020. Negotiations will start no later than thirty (30) days after receipt of this Communication and the proposals. . . .