A doubles pair should aim to play as a unit. This means two things – communication and coordination. You should to move as one. Most of the time this means moving sideways when your partner does. Advance up to the NVZ line when they do and move back down the court when they do. There are some situations when this basic rule cannot be kept, for instance when your partner has been lobbed and you run behind them to return it. If this happens your partner should switch i.e. move over to cover your side of the court which you have had to vacate. This also means you get out of the way of their shot as, if you don’t move, you would be standing in front of them. Your partner may call out ‘switch’ to alert you that they are going back to cover you.