This week I had a need to rename the Sub-Account. Well sub-account isn't an entity and it isn't listed in any of the places I could think of.
Given that we had a choice of hiding it or renaming it I did a bit of searching and low and behold thanks to the great team at Microsoft support we found the answer. To chance the display of the term sub-account to something different you edit Messages!! (Go Figure)
PS Twitter let me down on this one :( Despite having a focused following of great people some of these stranger questions get lost in the water flowing quickly under the bridge.