DEAR MISS MANNERS: I work in an office where my duties include taking phone calls from customers. Over the last couple of years, I have noticed that more and more people are using speakerphone to conduct calls with us. For some people, this is a very useful tool. For example, for the last few months my aunt was alive, she didn’t have the strength to hold a phone anymore. But for most people, the speakerphone is a convenience rather than a necessity. The problem that my co-workers and I experience is that sound is amplified a great deal when using a speakerphone. Someone setting a pan on the co…