Do you know?
The most important thing when waiing somebody is that the waier must wai from their whole hearts. In other words, the waier should sincerely pay respect to the waied or the wai receiver both mentally and physically.
How to return/receive the wai?
If somebody gives the other a wai, it usually means that they pay respect toward him or her. To return their good manner, the wai receiver usually wai back. That is, the wai receiver does the same to the waier (i.e. put their palms together in front of their chests), but they do not bow their heads.