Facebook has added a new feature named Voice on their platform.
Facebook Voice is enabled on Facebook Pages moderated by you.
When you open a page, you get use this feature to decide which identity you want to use to post, comment or like on that page.
Facebook spoke about this feature:
If you’re posting as the Page, click Change to [your name] to start posting from your personal account. You can switch back to posting as the Page at any time by clicking Change to [your Page’s name].
You of course already have the option to browse Facebook as one of your moderated pages.