If you’ve hard reset a fully operational fridge, then its temperature should remain the same while the reset is successfully executed. Moreover, a completely sealed and unplugged unit can maintain a safe temperature for food items for nearly 4 hours. Hence, you don’t have to go through the hassle of emptying the unit. Similarly, the freezer temperature remains stable to preserve frozen food between one and two days, even if the unit is unplugged.  However, if you need to reset the showroom or demo mode, it will take some time for the unit to cool, meaning you won’t be able to store food in it during that period. And depending on the model and size of your fridge, it may take anywhere between 2 and 12 hours for the unit to become “functional.”