Standing orders: not modifiable for six months absent agreement; modifications require application to certifying officer. Section 35 prescribes a six-month moratorium during which certified standing orders are not liable to modification except by agreement between employer and workers or their representative. Thereafter, an employer, worker, trade union, or representative may apply to the certifying officer for modification in the prescribed form, filing proposed changes and, where relevant, a certified copy of any agreement; the Code's certification provisions apply to such modification applications as they do to initial certification.