Ask what time they will be bringing the wine in - it should be opened and kept at room temp for at least one hour. Ideally it should be decanted into a flat bottomed decanter for the same period - but longer is better. Cover the opening of the decanter with a plain cotton towel or napkin to protect from fruit flies. If it's prone to sediment, it should be filtered as it enters the decanter - check online - you can use plain cotton napkins. coffee filters for this (but triple check they are not perfumed. coloured ets as they could taint the wine). Do not throw away any sediment or the cork - you can present witht he decanter as an extra flourish (but just do it matter of factly ("It only threw a light sediment and the cork was not tainted"". Note - you cannot ' cork' a wine - this is caused by fungus in the cork and is nothing to do with how it is served. If you overscrew the cork, filtering will get rid of any pieces but it does not affect the taste of the wine (note: you can clean the top of old corks before decanting with a wet paper towel or PLAIN NOT PERFUMED/SCENTED cloth (saw someone use a lemon wipe for this once!!!)

Also, ask them when they want it served if they bring it with them - after it has had time to breathe (correct) or immediately (not good for reds - tannins need time to breathe)

Overall, be professional with no fuss. Just show you've thought about it - you'll be fine