How to say "You can use 반말" in Korean
If somebody is speaking in 존댓말 with me but I want them to be casual and use 반말 what should I say? Something like "You can use 반말" or "Let's use 반말" or "It is okay to use 반말?" How would I say this in Korean?

Question

Answer

그냥 반말 해도 돼요~~ ^^
그냥 말 편하게 해도 돼요~~ ^^
그냥 반말해 ^^

Answer

In some situations, you should use '높임말' while the other person uses '반말'.
formal style : (when you talk to older person or respected person..)

말씀 낮추세요.
말씀 편하게 하세요.