34. Notice of change.- Any employer intending to effect any change in the conditions of service applicable to any workman in respect of any matter specified in the Fourth Schedule to the Act shall give notice of such intention in Form E. The notice shall be displayed conspicuously by the employer on a notice board at the main entrance to the establishment in the Manager’s Office : PROVIDED that where any registered trade union of workmen exists, a copy of the notice shall also be served by registered post on the secretary of such union. | 