Due to their colonial past, many inhabitants of the SARs hold some form of non-Chinese nationality (e.g. British National (Overseas) status, British citizenship, British Overseas citizenship or Portuguese citizenship). However, SAR residents who are Chinese descent have always been considered as Chinese citizens by the PRC authorities, an exception to this case is Macau, wherein residents of Chinese descent may choose Chinese or Portuguese nationality. Special interpretation of the Nationality Law, while not recognising dual nationality, has allowed Chinese citizens to keep their foreign "right of abode" and use travel documents issued by the foreign country. However, such travel documents cannot be used to travel to mainland China and persons concerned must use Home Return Permit. Therefore, master nationality rule applies so the holder may not enjoy consular protection while in mainland China. Chinese citizens who also have foreign citizenship may declare a change of nationality at the Immigration Department of the respective SARs, and upon approval, would no longer be considered Chinese citizens.