This is a frequently used Korean phrase, but while having a fluxuating definition, it could only be fully understood using context clues. The phrase "How Dow" commonly substitutes hello, goodbye, how are you, thank you, have a nice day, etc.
"Oh! How Dow to you sir!"
"Why, how dow!"
"How dow for the gifts you gave me the other day"
"Oh yes. Dont forget to give a how dow for your grandma for me too"