Yesterday marked the first day on the job in his own right for Matt Comyn, the Commonwealth Bank's new chief executive officer. His appointment, stepping up from head of retail banking to the top job, set off a chain reaction of executive departures and reshuffles. Comyn's first publicly observed action was to set an early tone of contrition, with an email to staff that included phrases such as:"We have made mistakes. We have not done enough to protect our customers. That starts with me and our senior executives" he said in an email to staff."We have been too slow to fix mistakes and we have failed to meet some important regulatory and compliance obligations. This is unacceptable.""There is a lot for us to be proud of."But the reality is that while we have got a lot of things right for most of our customers, we haven't got it right for all of them."In order to have a lasting effect, though, Comyn's words will need to be backed up by a degree of customer service that has too often been seen as optional by key staff in recent years - as evidenced by the inquiries and court cases being run.  CBA has also to weather the royal commission into banking misconduct, which has already had a rollicking start, with many more confessions to be unearthed in coming months.In this regard, Comyn's note could easily be mistaken for a piece of window dressing: a final report on CBA is due from the Australian Prudential Regulation Authority on April 30."We will hold ourselves and each other accountable. We will promptly address the issues raised by the royal commission and our regulators," Comyn wrote.One issue that will need addressing - not just by CBA - is the complete disregard to customers' best interests already disclosed in round one of the royal commission.With round two of the commission getting underway next week, covering wealth management and advice, Comyn will surely be tested.