You can change your app description (we do every few months or so as we add new features), but changing your app's category will likely get the Apps Team poking around. The reason being, you wouldn't have the need to change your app's category unless you made substantial changes to the original (and approved) product.
IIRC, you can reach out to the apps team directly at firstname.lastname@example.org to inquire about this.
|3 hours ago|
|4 hours ago|
|9 hours ago|