Luxury department store operator Neiman Marcus is testing a new iPhone app to help enhance the relationship between staff and shoppers.

Users can find out which sales associates are on duty at a store. Likewise, when a customer checks in to a particular store, sales associates are notified and can access information about the shopper’s buying history.

The innovations follow Neiman Marcus research that found customers who shop with the same associate three times spend almost 10 times more than those who go to a random assistant.