How to ignore or modify midi specific volume/pan value

I’m using SE3 3.3
Then I drag drop a mid file into cubase
And I belivw those info write in the mid file
cubase auto add Halion plugin and config it

But when I try to modify the mix setting inthe Halion, The volume and pan will reset to the mid specific value, Can’t change it at all,
How to change it ?
Ignore the mid internal valume pan setting ?
How to modify mid file delete or modify the value ?