Thanks for asking, it really means a lot. Personally, it helps me when the other person just acts normal I guess. Don't be alarmed or try to finish sentences for them, I know it seems helpful but it's super frustrating. Just try to be patient and get a good rhythm going, consistency and a good flow will usually make people more comfortable. Also, I don't know how older people are but younger kids especially find stuttering amusing and they start laughing. That is one of the worst experiences I've ever had to deal with. Overall just be nice and patient and that's all you can really do without seeming overbearing. If the person decides to be transparent about their stutter then it's a different story, just go with the flow I guess. Again, thank you for asking.