I am not a picky eater and like Citrico's. However, I have 2 adult children who are very picky and they thought Citrico's was one of the worst meals of their trip.
There's a new menu at Citricos so I would watch for that to be posted. Wish I could remember who took pictures of it.
Anyway, in general WDW restaurants are great about accommodating things like that if it involves something they can do with what they have. So if you want a steak without the sauce...no problem. Substituting the starch with another on the menu...fine.
If you are pure beefesteak and mashed potato folks, I agree with CDtommie. But if it's simply a matter of removing some sauce or substituting a vegetable, then as BCV23 suggests, you should be OK.