Accounts set up as channel managers and financiers have the ability to log in as a downstream partner (Contractor Org). 

To log in as a downstream partner click on the top left menu icon. 

Select Log In As Contractor Org.

The "Log In As Contractor Org" window will appear. Select the name of the downstream partner you would like to log in as, enter your password, and click Log In. 

You are now logged in as the downstream partner selected. To verify which organization you are logged in as click the menu in the top left corner. The organization name you are logged in as will be displayed at the top of the sidebar.