This is a feature in Customer Support that lets you assign your tickets to users based on your rules.
Selecting a user
You can only select one user to assign, unassign and reassign customer support tickets, and that user needs to have a Customer Support licence.
Only users with a Customer Support licence will be shown in this option.
How to add Customer Support licence to a user
Selecting a role
Roles can contain multiple users.
If you select a role, Upsales randomly picks a user with that role who has a Customer Support licence.
The user assigned to the ticket will see it in their ticket list.