change whole library style

I am a very new user to endnote. I have a single library of about 150 references which I entered using APA 6th. However when citing in text is kept on putting all six authors names instead of just one and et al. I found out how to edit the style and now have a style called APA 6th Copy that uses the et al format for references with more than 3 names. 

Now I want to apply this to all my other references, I have tried highlighting all the library and selecting the new style but it is not working, andy advice out there?

Thank you


I suggest that you take a bit of time to review some of the youtube training videos to get a feel of the software.  Check the Training forum here for massive numbers of resources, but start with the suggestions and Quick Start PDF here.

The output styles adjust the information in the records to match the output style in the document you are working on.  The output style you choose there will adjust all the cited records in that documents bibliography (on the Word 2007/2010/2013 ribbon for example). 

While in endnote, to preview a record layout in a different output style, you need to change it in the toolbar of the endnote program.