What can I talk about on the phone with an unfamiliar elder and how to start better?

It is suggested that the subject can use holidays or special festivals to call the elders you mentioned. After making a phone call, you can introduce yourself first, then talk about weekends or holidays and say some holiday wishes, which is actually a simple greeting. After that, you can ask your elders how they are recently, whether the temperature at home is good or not, and so on. Be sure to keep warm in winter, put on more clothes when you go out, and don't catch a cold. You can also ask your elders to buy more delicious food. Don't be reluctant to give up anything. After all, their elders save food and clothing, and consider the problem from their starting point. So everyone likes it.