Etiquette is about having good manners and making people feel comfortable and valued. Most people at one stage have made the mistake of calling someone by another name or forgetting their name all together. We are only human but it can be incredibly humiliating.

A great way of getting yourself out of hot water is by owning your mistake and using a bit of humour to lighten the situation. For example, I am sorry I have a terrible memory. People are generally forgiving but then make an effort to remember their names to not make a repeat incident. 

If you are on the receiving end of this situation. The context can happen verbally in person or in an email. It can be frustrating and you may feel unimportant. Do you say something or let it go? Do you change your name? You can turn this around by making a polite but memorable correction. Give them you actual name but try using humour to not fuel the awkward situation.

"I have always wanted to be called Jan but my you can call me Jen."

See the Australian Finishing School 'AFS' live interview on ABC Radio http://www.abc.net.au/radio/adelaide/programs/drive/drive/9604718