They will not allow you to exchange if you use the item. However, if the "faulty" issue strongly involved on the item, they will first try to get the item fixed. If exchange is allowed, they will need to check the item closely and approval from store manager. Not a comfortable issue here. If they know u r regular buyer or good customer, sometimes they do go extreme to track down the item and replace the item even it is used already. It happened to me. My case went more complicated as the item was bought in HK by my family members and the item was not in store anymore. The manager and SA went track down the whole Australia for the very last item available. They succeeded and my item exchanged to a new one. So, it really depends. Good customer relationship is important.