You can modify a system, add references to it and delete it with the correct permissions:
You can also view the system activity log to see a list of the recent management activities carried out.
In the Systems tab of the Assets tool, click a system to open it.
To add assets to a system, click Add assets.

Select the assets that you want to group into this system. Use the search field and filter icon
at the top right to search for assets by name or filter for certain assets respectively.

Click Add assets.
To add other systems, from the same Systems page, click the blue arrow icon next to Add assets instead,
and select Add systems.

Select all the relevant systems. Use the search field and filter icon
at the top right to search for systems by name or filter for certain systems respectively.
Open a system.
Edit the status or category.

Open a system.
Click Add references.

Select the project item that you want to reference and use the window to select an existing item or create an item.
Open a system.
Click
at the top right.
Confirm the action by clicking Delete.