If a person fasts in one country and then travels to another country that is one day behind in the start of the month, must he fast with them even if he completes 31 days of fasting?

If a Muslim travels from a country where he began fasting at the start of the month to a country where the breaking of the fast (Eid al-Fitr) is delayed, he should continue fasting with the people of the new country until they break their fast, even if this exceeds thirty days. This is based on the Prophet's (peace be upon him) saying: "The fast is the day you fast, and the breaking of the fast is the day you break your fast." However, if he moves to a country where the sighting of the new moon occurred earlier, he should break his fast with them and make up for any missed days if he has not completed twenty-nine days [of fasting].