The Booking.com rep (extremely polite) answered...
A Booking.com customer review by GetHuman user ~cehiggins from November 24th, 2017
Background on ~cehiggins's case
GetHuman: ~cehiggins - can you tell our other Booking.com customers when your case took place?
~cehiggins: Sure. It was late at night, on November 19th.
GetHuman: Did you reach out to Booking.com, and if so, how?
GetHuman: And which of these common Booking.com customer issues best describes the reason you wanted to talk to them?
(Shows ~cehiggins a list of common Booking.com problems)
~cehiggins: "Change My Booking" was why I was trying to call.
~cehiggins's review of Booking.com customer service
GetHuman: So how would you sum up your experience for GetHuman's Booking.com customer community? We'll censor any IDs, numbers, or codes and any inappropriate words here out of respect to the millions of other customers using this resource.
~cehiggins: The Booking.com rep (extremely polite) answered on the first ring after I received the recording. I realized I had booked a smoking room and asked for a non-smoking room. She called the hotel directly and put in this request for me.
GetHuman: Let's quantify your experience contacting Booking.com. On a scale of 1 to 5, how easy is it go get help on a Booking.com problem?
~cehiggins: I'd give them a two out of five for ease of finding your way to help.
GetHuman: What about quality of communication. How would you rate that on a 1 to 5 scale?
~cehiggins: I'd give them a five out of five on communication.
GetHuman: And what about Booking.com's ability to quickly and effectively address your problem?
~cehiggins: For that I would say two out of five.
GetHuman: And finally- any advice for other Booking.com customers?
~cehiggins: Call them early in the day or late. Don't forget any personal or account information you might need for Booking.com to know who you are.
GetHuman: Well there you have it. Some useful feedback and words from ~cehiggins taken from his Booking.com customer service problem that occurred on November 19th, 2017.