Bringing in the big guns, otherwise known as the BBC ...
Formal greetings How do you do? is very formal and is not used very much, especially by younger people, these days. It may be used on first meeting and accompanied by a formal handshake when both partners issue the same greeting. The reply to How do you do? is How do you do? Then it would be a matter of getting straight down to the business in hand, e.g. ‘I see that your company has been performing very well in South East Asia...'
I can't link directly to the page until I pass 30 messages, but it's in the first five results you get by typing -- response to "how do you do" -- in Google.
If you were to look at the "Read Me First" thread at the top of the forum index page, you would find a section called English FAQs, which contains links to threads about many frequently asked questions about English usage. One of those links is Greeting - How are you? How's you? How's it going? How do you do? and it will bring you to a very long list of threads on this very topic.
This thread is now closed.
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