A common issue is a user who has a role higher than Agent only being able to see the same things as an agent.
You might have made someone an admin in Users & Workspaces > Users but they report to you that they can only see their own conversations and data.
This is usually because they have been restricted to the Agent role in a Workspace. This allows you to have a user as an agent in one Workspace but a higher role in another. However, this sometimes can cause confusion.
If you have a user who should be able to see more than they can, you can follow these steps:
Go to Users & Workspaces > Choose Workspace
Check if you can see this next to the user name
Change their role to the correct one