When the routing is activated via Settings > Miscellaneous > Hide conversation of other agents agents see only their own conversations and can select the unassigned ones.

• Agents menu: displays the agents’ menu to assign the active conversation to another agent.
• Routing if offline: if the conversation is archived and the user reopens it in the future by sending a new message, if the assigned agent in the conversation is offline, the conversation is assigned to another online if there is at least one, otherwise to no agent.
• View unassigned conversations: allow agents to view the unassigned conversations, when an agent replies the conversation is automatically assigned to him and the conversation is removed in real-time from the admin area of the other agents. Check this option to enable the manual routing.