When someone gives you a bracha you should respond “Amen” and also give a bracha back such as “v’chein l’mar” or “baruch tihyeh”
It should also be noted that “shkoyach” does not mean thank you. It is a bracha as well (it should be “yasher koach”). Someone once told me that by saying “shkoyach”, you miss an opportunity to say “thank you”