In the H90 Control Edit page: check out the small icons bottom right.  (18) in the link below:

https://cdn.eventideaudio.com/manuals/h90/1.9.7/content/h90-control/edit.html.

HS1 – HS2 – HS3

• Click on one of these, and it’ll (probably) show all of the parameters grayed out.
• Click on the upper right of any parameter to (+) and adjust the now active value.
• PGM reverts back to show all of your base Program settings
• That particular HSx Performance Parameter should now toggle between settings