If you use CRM Online on the Office 365 platform, you will notice that the main fields on the user record are read only. This is because user information is managed in Office 365 and synchronizes to CRM.
For example, say you have a CRM environment that already contains active users, and you want to change the format of the full name on the records. Say you want to change it from firstname lastname to lastname, firstname. When you change the format setting in CRM, it only applies to new users. Existing users will keep their existing format for full name.
The answer is to have your Office 365 administrator change something about the user’s name in Office 365. The change will synchronize with CRM, causing the full name format to be updated in the process. Just make sure you wait for a little while–it takes a little bit of time for changes to sync from Office 365 to CRM.