Solution:
Follow these steps to remove undesired agent:
Step 1
Go to Administration | Agents | Agent Status | Select issued Agent | Stop data collection | Deactivate | Delete
Step 2
Go to Management server | Servers | Retention policies | Investigate Objects for Cleanup | Data Management Browser located in the bottom left corner | Expand Host Model | Expand Host | Type the name of the server in the search field | Click the delete icon and press yes
Step 3
1- Go to Administration | Tooling | Script console |
2- In the search field remove the word "Abstract" and type "Host" click on highlighted Host then click List instances
3- Select require host to be remove
4- In the Properties tab look for "uniqueid" and note this number
5- Go to the scripts tab |Click Add | Remove text from the "Enter Script Text" windows
6- Paste the following script
ts = server["TopologyService"];
obj1 = ts.getObject("69e38fcb-dcb6-41b2-86ad-5e93df504c73");
ts.deleteObject(obj1);
7- Put the correct Id noted from step 4
8- Click run or save for future uses, the output is "null"
9- Refresh the page and make sure the host is removed
Once removed make sure under the host dashboard that the agent is not listed.