My brother in law and family recently moved fm USA to China to teach. They want to visit Kenya where we live. His wife has to travel out of china with a temporary passport as hers expires soon. South african temporary passports are valid for 1 year, so going back will not be a problem for passport validity, but, will they be allowed to return to china on the visa which is in the old passport. Do they have to get it transferred, and travel with both passports?