If you want to assign an owner of a device connected to a virtual Administration Server, first switch to the virtual Administration Server:
In the main menu, click the chevron icon () to the right of the current Administration Server name.
Select the required Administration Server.
In the main menu, go to Users & roles → Users.
A user list opens. If you are currently connected to a virtual Administration Server, the list includes users from the current virtual Administration Server and the primary Administration Server.
Click the name of the user account that you want to assign as a device owner.
In the user settings window that opens, select the Devices tab.
Click Add.
From the device list, select the device that you want to assign to the user.
Click OK.
The selected device is added to the list of devices assigned to the user.
You can perform the same operation at Devices → Managed devices, by clicking the name of the device that you want to assign, and then clicking the Manage device owner link.