Install Fleet Server on same machine as Elasticstack

I have installed Elasticsearch 8.1.3 and Kibana on an Ubuntu machine and has been running for a while.

I wanted to add Fleet Server to the same machine but when I follow the steps here, it says elastic agent is already installed.

Is there a way to modify the existing server config to add a fleet server running on the same machine ?

I am aware that it might not be the best practice but I am trialling it out