Hey @Sanjay, to add a robot to an existing environment follow these steps: 
- In the Environments page, click Edit for the corresponding environment. The Manage Environment window is displayed.
 
- Select the corresponding check box for the Robot(s) you want to add.
 
- Click Close. The Manage Environments window is closed and your settings are saved. 
 
Although you cannot add a Robot to an environment if a process associated with that environment is already deployed on the Robot.
To remove a robot from an existing environment following steps can be performed:
- In the Environments page, click Edit for the corresponding environment. The Manage Environment window is displayed.
 
- Clear the corresponding check box for the Robot(s) that you want to remove.
 
- Click Close. The Manage Environments window is closed and your settings are saved.