AMP Bank has undergone an overhaul of its governance processes that is set to transform the way the subsidiary operates within the shrinking financial services group.Details of the changes were revealed by the AMP group board in the company's 2019 annual report published on Wednesday.The restructure, which tightens the AMP group board's control over the subsidiary, effectively marks a reining in of the autonomy of the banking arm.Since it was launched in February 1998, AMP Bank has operated essentially as a stand-alone unit that was an add-on or complement to the core wealth management business.The key marker for its autonomy within the group was always the composition of its board, which typically included heavy representation of AMP executives and independent directors from outside the group.However, that all changed three weeks ago when AMP group chair David Murray effectively sacked the bank's old board and replaced it with the listed parent's ten directors.The move officially puts Murray at the helm of a bank again and most likely erodes the ability of AMP executives to set the subsidiary's strategic direction.The overhaul might raise questions about the future of AMP Bank's chief executive, Sally Bruce, who managed to grow the subsidiary's balance sheet and bottom-line last year as the rest of the organisation descended into chaos.Bruce has been tipped from the AMP Bank board along with group chief financial officer, Gordon Lefevre.External non-executive directors Trudy Vonhoff and Wendy Thorpe have also lost their seats following the shakeout.Time will tell whether the group directors will be able to build on the bank's growth momentum.Under the new arrangements, AMP Bank board meetings will be held concurrently with those of the parent.The audit and risk committees of the bank and the group are also merging."The boards of AMP Limited and AMP Bank (and their respective risk and audit committees) will meet concurrently going forward (where appropriate), with a view to improving decision-making efficiency, reducing duplication and streamlining management reporting," the group told shareholders in the annual report."During 2019, the AMP Limited Board intends to continue to review subsidiary board governance across the broader AMP group."Murray's preference for a more centralised governance structure gives him more leverage over the bank's management and its strategic direction than previous AMP chairs cared to take on.That might make for a more testing interaction between the bank's board and management, but it's also an indication that the bank is being viewed as a key driver of the group's restoration and future.Under Bruce, the subsidiary has demonstrated resilience and emerged as a reliable source of earnings - seemingly immune from the damaged master brand.AMP Bank's full year operating profit of $148 million equated to a commendable return on capital of 15 per cent.With other core businesses faltering, Murray is now describing the bank as "important" - and peppered throughout the annual report are references to the subsidiary as "core".If the retail super fund outflows persist, it's a fair bet that AMP will allocate increasing licks of its $1.65 billion surplus capital to