Subhan Timber Workers Association (PPST) is a registered trade union. It is recognized by Subhan Timber (ST), a logging company in Sabah as the trade union representing it employee. On 2nd March 2018, PPST sent an invitation to ST to hold a collective bargaining session to discuss the issue of promotion. PPST suggested that the general procedure for promotion application for general workers at ST be simplified as most of them are unable to complete complex application documentation. A collective agreement was reached between PPST and ST on this matter on 29 March 2018 and it is in force for four (4) years. This agreement was taken cognisance by Sabah Industrial Court on 12 April 2018.

At the beginning of 2020, ST's new management reviewed the promotion procedure for all positions in ST. They are of the view that the collective agreement made in 2018 is invalid as it relates to the issue of promotion which is the exclusive right of the employer. They also argue that applications for promotion in ST should be tightened to avoid too many applications at one time. Therefore, ST directed that all promotion applications be made online and must be accompanied by supporting documents. PPST is not satisfied with this decision and intends to take action against ST.

Analyse of the above situation. Support your answer with the relevant legal provisions and case law. Refer to the employement and industrial relation law