problem transforming table to First normal form
It is better to create a separate table for agent_status. Now it seems easy to add agent_status column in agent table itself. But with my little experience I can tell you, business requirements may change in future, sometime too often. Our data model must be developed in a way it should accommodate all the future requirements and changes without much alteration on the underlying model.

In some cases, business will required to track history of agent_status over a period of time (@Ziggy) and, there are possibilities, where you are required to add new status values, also you may required to change status name in future in order to accommodate your business requirement.

If you are sure that, your business requirement will not change in future, you can add agent_status column in agent table itself, or else create a separate entity named agent_status.

I hope this answer will give you some idea, Thank you.