Commonwealth Bank chief executive Matt Comyn has been making changes to his senior executive ranks since he took over from Ian Narev in April last year. There can't be too many senior roles left to change.In his latest move, Comyn has hired a South African banker to run CBA's business and private banking division. Mike Vacy-Lyle, who is currently chief executive of FNB Commercial Banking, a division of FirstRand Banking Group, will join CBA in February next year.He will replace Adam Bennett, who is leaving the bank after 15 years. Bennett joined the bank's group technology unit in 2004 and was chief information officer for the retail and business banking divisions during the period when the bank's core banking technology was being rebuilt. He was appointed group executive business and private banking in 2015.Vacy-Lyle is a chartered accountant with a track record in managing continuous improvement and simplification programs.CBA also announced this week that Jason Yetton, who has been leading NewCo since October last year, will leave the bank in January. NewCo was formed to handle the demerger of the bank's wealth management and mortgage broking businesses.In March, the bank suspended the demerger to focus on customer remediation and the implementation of recommendations of the Royal Commission. One business that was sold off was Count Financial, which was sold back to CountPlus.The bank said its exit from its aligned advice businesses "remains on track" for completion by June next year.In August, Comyn made two senior hires. Carmel Mulhern was appointed group executive group general counsel and governance. Mulhern is moving across from Telstra and will start in January next year.Scott Wharton was appointed to the new role of group executive program delivery. Wharton moved to CBA in 2016 from Citigroup, where he was global head of enterprise supply chain. At CBA he led the implementation of change programs to upgrade the bank's technology and regulatory operations.In June, the bank appointed Priscilla Sims Brown to the new role of group executive marketing and corporate affairs. The new role was created "to allow greater focus on how we engage with our customers, stakeholders and the broader community."Sims Brown joined from Emerge.me, a US digital healthcare start-up. Before that she was chief marketing officer at AXA Financial in the US.In June last year, the bank made six changes to its senior executive team. Nigel Williams was appointed chief risk officer, joining from ANZ.CBA general counsel David Cohen was appointed deputy CEO.Pascal Boillat moved over from Deutsche bank to take up the role of group executive enterprise services and chief information officer, replacing David Whiteing.Sian Powell was promoted from running the bank's customer contact centres to group executive human resources, replacing Melanie Laing.Andrew Hinchliff, another internal appointment, was made group executive institutional banking and markets, replacing Kelly Bayer Rosmarin.Angus Sullivan, who joined the bank in 2012, was promoted from head of retail strategy and innovation to group executive retail banking.And in May last year, Alan Docherty was appointed acting chief financial officer, following the