How could I address a person...?
The initial official and/or proper stage since meeting for the first time is past and the relationship is friendlier.
How could I address someone who is
10 years older?
20+ years older or my parents' age?
40+ years older or my grand parents' age?
Thank you.

Question

Answer

Try specifying your question with some English sentences, examples to illustrate what kind of dialogue you want to have with a specific person.