Sometimes EndNote will start putting initials next to the authors' names in your in-text citations. This is because it has registered your authors as different people, and it is programmed to use initials to help readers tell the difference.
There are times in APA when you should use initials to distinguish between two authors with the same surname (see this blog post for more details), but if you find EndNote is using too many initials incorrectly, you can edit the style.
In EndNote go to "Edit > Output Styles > Open Style Manager. Select the APA version you are using and click the "Edit" button. Then go to "Ambiguous Citations" under "Citations" and uncheck the "Include author initials or full name in citation" option.
You may also need to go to "Author Name" and uncheck the option to "Use initials only for primary authors with the same name".