Go to the Menu by swiping from the left edge of the screen or clicking the hamburger menu button as seen below.
Next, select Change System
Tap on System in the upper left corner of the screen and the system menu will appear.
Tap Change System, and a list of your systems will appear, from which you can select the system you would like to connect to.
You will then be brought to the first dashboard you have for that system.
Note: This feature is only available to MyHS Premium subscribers. More information is available here.