What Privilege's are needed to update agent field (Assigned To) in help desk

Summary:

Assigned the Next Gen Manager role however, the Manager is unable to make changes to the Agent Field (Assigned To), when assigning Next Gen Admin role the admin is able to change the Agent Field (Assigned To).

My question is what Privilege allows the ability to change this field so I can add it to a custom Manager role.

Content (please ensure you mask any confidential information):

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):