You are the company secretary of ABC Limited (the "Company"), a limited company incorporated in Hong Kong, whose shares were listed on the Main Board of the Stock Exchange of Hong Kong. The Company has 500 million issued shares. The board of directors consists of two executive directors, one non-executive director and three independent non-executive directors. The board received a resignation letter from Johnny Wong ("Mr. Wong"), an independent non-executive director of the Company on 6 September 2020. The board wishes to appoint Mike Lee ("Mr. Lee") as an independent non-executive director to fill the causal vacancy arising from Mr. Wong's resignation. Mr. Lee is a former partner of the Company's audit firm. He retired from the Company's audit firm on 31 August 2018 and also a registered shareholder of 5,000 shares in the Company.

Required: As the company secretary of the Company, you will need to write a memorandum to the board seeking further information from them to fulfil your compliance duties in the context of the Companies Ordinance and the Listing Rules.