In order to assign an activity to an agent, open it via the Activities tab and change the Responsibility. If you assign a different staff member (Responsible) than the one currently in the record, the activity or task counts as delegated. The staff member then responsible can see this activity in their Entry Portal if the activity is dated accordingly and needs to accept the task, or refuse it, giving a reason. To do that, the new agent opens the activity and clicks the Status button, allowing them to handle the delegation accordingly.
Assigning activities to an agent
See also: Status of an activity