How do I best change the middle name on my passport to the middle initial I use on everything else?

I am trying to make sure all my documents, including my passport, match with regards to my middle name/initial. My name on my birth certificate was Kate

Source: http://www.us-passport-service-guide.com/how-do-i-best-change-the-middle-name-on-my-passport-to-the-middle-initial-i-use-on-everything-else.html

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