Checked my bank statement and shocked to realize the $300 annual card fee incurred in early March!  I could have called the hotline but it was too much a hassle.  Instead, I voiced out my request via their online chat system built within the HSBC app.  Turn out it is quicker than I thought! I just made the request and indicated the card number (last 4 digits).  Take about 15 minutes for them to complete the request.  No other request for information is required.

Anyway, the online support still advised me to do it myself by quoting the instructions at the end of the conversation (in Chinese).

日後,您只需按以下步驟遞交申請:
– 致電熱線:+852-2233-3000。
– 選擇語言
– 按3-#-0-1
– 根據指示説明輸入所需的信息
您的申請需要經本行審核,會在3個工作日内完成。
如有簡短的系統語音提醒,您可聽完後再輸入快捷鍵。
For my future reference.