If you have a Service Desk Database Administrator user already configured in Service Desk, and for some reason, in example, due to some security policy you need to change it, so you must follow the steps described.
This document explains how to create a user for the SDM (Service Desk Manager) directly in the database.
CA Service Desk Manager - 14.1 / 17.1
To create the new SDM user, follow these steps:
1) Logon to the database through SQL Server Management Studio and right click the ’Security > Logins > New Login’. In this example, a new login was created as ‘DeskService’ (The new login properties must be the same as the previous Service Desk login).
2) After creating the new Login, go to ‘Databases > mdb > Security’, right click on ‘Schemas’ and create new Schema. In this case, the new Schema has the same name as the Login: ‘DeskService’. The owner for this schema, is the Service Desk Server local user, in example: ‘DeskService’.
3) Create a new Database User right clicking ‘Databases > mdb > Security > Users’. In this case, the database user name is also ‘DeskService’. Set the new Login and the new Schema to the new user. Use the same properties as the previous Service Desk user.
Before doing any work in Databases is a good practice to always make a backup of it.