Click the blue circle on top of the page -> Show all parties. On the page All you parties you can check/un-check the box for Show all sub-entities and Show deleted entities.

You will only be able to see deleted entities that you had roles for at the time of deletion.

If you want to search for messages across all parties you can represent, you can do so by clicking Search across parties on the page Show all parties.

From this page you can search across all or some of the parties you can represent. You'll also be able to save thos searches.

In order to represent anyone other than yourself, you need to be given a single service or a role, for the party in question.

The general manager/chair of the board/main administrator of the company can give you access.