Reformatting references once their in Word

Let’s say that I submitted a paper to Nature, and then it was rejected, and I want to submit it to another, such as the Journal of Cognitive Science.  How can I change the format of the references in the word document without manually deleting and reinserting each one (because there are over 300 references)?  


Reformatting your manuscript using different output style?

I respectfully suggest to go through this training.