How to assign multiple agents to one ticket?

Yes, you can assign multiple "technicians" or "agents" to one ticket. To enable this feature go to "Admin panel - General settings - Allow assigning a ticket to multiple technicians".

After enabling this setting you can click the "add secondary assignee" link in the ticket-details view:



There's still one "main" technician in a ticket, additional assigned agents are called "secondary assignees", they see the ticket in their "assigned to me" ticket-queues, but that's basically it. All reporting and tracking (like "time spent" or "average response time") for a technician is calculated for "main" technicians only.

We actually advice against using this feature unless you know what you're doing, since it complicates workflow for both support teams and end-users.