Your clients' are unable to uninstall the Desktop Central Agent from Add/Remove Programs, as there is no provision available to do the same.
You may encounter this problem if, you have enabled the "Disable Uninstallation Option in Control" check box under Admin -> "Global Settings" -> "Agent Settings" while deploying agents to computers.
Revoke User Permissions to Add/Remove Programs
If you want to allow your users to uninstall agent from client machines,
The update will get reflected during the subsequent communication between the Agent and the Server. And the users will be able to see options to add or remove under the Add/Remove Programs section.
Uninstall from Client Machines individually
Using this method, you can manually uninstall the agents from the desired client computers.
Applies to: Agent Uninstallation, Manual Uninstallation
Keywords: Agent Uninstallation, uninstall agent manually, Desktop Central Agent removal, Desktop Central Tray Icon