The BBMS/BBPS usernames cannot be changed once assigned to your organizations Site ID Number, this is because the organization is registered with a BBMS/BBPS account upon creation. However if mistakenly the account is created under an employees name, additional BBMS Accounts can be created and attached to the same Site ID Number to correct any mistakes with username designation. Please see Article : How to set up/register additional BBMS accounts for further information. 

When creating your BBMS/BBPS accounts consider using a username pertinent to your organization such as OrgNameMS or OrgNamePS respectively.
DO NOT use your personal information to create the organizations username for BBMS/BBPS example: JohnSmith .