Yes. You can assign as many agents as you want to any ticket. When you assign any additional agents to a ticket they will be treated the same as the main agent assigned and will be notified of any changes made to the ticket.
When looking at your ticket (on a Desktop) you will see a section called "Additional Agents". There you can add agents.
Keep in mind that you cannot re-add the current assigned agent to the ticket as well as the user who is the requester since they are already associated with the ticket itself and will already receive any correspondence.