The Recalibration station is made available when upgrading the Tech wing
This area allows you to reroll Weapons and gear to change the bonuses associated with it. Although in a limited fashion. Each reroll will cost you Credits.
You can only reroll to change one property of the item and once you have tried a reroll on that item you will only be able to make further rerolls of the same property and each new attempt will cost an increasing amount of Credits.
The interface shows you, for each item, the bonuses associated with it and the potential outcomes of any reroll so you will have an idea of what you might get. You can also see the cost for the change.