Except in the cases of full sex change and the person I'm reading for fulling changing over name, lifestyle, and a surgically and hormonally altered body, I've always found that the original name is what to refer to.

The new name will effect the response you get from people who meet you as the new name, not people who know you as your original name, but the old name will always exert the most force on your experience. The name change is almost like an event chart. I tend to look at name changes as spice or an overlay to the original name. If it is a name change based on wishing to rename one's self for purposes other than marriage or a sex change, then I tend to read the name chart more in terms of what experiences and energy you are wishing to pull into your life. For example, if you have a lot of 2s in your original name, but have chose a new name with a lot of 1s, it indicates a time in your life when you wish to be less passive and relationship oriented and more decisive and independent. Nicknames are the same - they hone an energy, perhaps allowing you to present an image that otherwise would not be presented by your legal given name.