Generally speaking, Awesome Support only allows you to assign a ticket to one agent at a time.  A ticket can be transferred to another agent but it is, by default, a single agent per ticket.

Starting in version 3.6. support for up to two additional agents is provided.  They are called the Secondary Agent and Tertiary Agent.  To use this feature you first need to enable it:

• Go to the TICKETS->SETTINGS->FIELDS Tab
• Scroll down to the MULTIPLE AGENTS section.
• Check the box next to Enable Multiple Agents Per Ticket

Once enabled, two new fields will show up in the Additional Interested Parties tab on the ticket:

Even without the multiple agents option enabled, any agent or administrator authorized to view the ticket could submit a reply, close the ticket or perform other ticket-related activities. And, any agent or administrator with access to a ticket can fill out data to add additional agents to the ticket.

However, by formally adding a secondary or tertiary agent is added to a ticket, those  agents will gain some benefits.  They will:

• Receive notifications about events on the ticket just like the primary agent
• Be able to respond to the ticket via email (if the Email Support Add-on is purchased and enabled)
• See the ticket in their list of tickets
• Be able to reply to the ticket, add notes and do everything that the primary agent can do.

Additional Options

• You can use the Power-pack/Productivity add-on to add unlimited email addresses to a ticket that can be used for notifications.
• This article on agent collaboration offers some more insights into how you can use Awesome Support for coordinating ticket support activities among multiple agents.
• This article on notifications lists all the ways you can use Awesome Support to keep your agents and customers updated.