How do you change who you are commenting as on Facebook Mobile

Switch Identities for Posting/Liking/Commenting

In the posting area at the top of your Page’s Timeline, click the icon of your profile pic. A menu will drop down listing your personal profile name as well as all the pages you have admin privileges for.

If you select any of the identities other than the one for the Page you’re on, the icon will change and the “What have you been up to?” message will change to “Write something on this Page.”

And when you do so and then post it, you’ll be notified that you wrote on the page and you can see the post in the Posts to Page section.

When you want to Like or Comment on a post on your Page, you’ll see those same dropdown options above the comment box.

And then when you Like or Comment on it, it’s just like any other person doing so.

That’s it! Pretty simple once you see it, but it’s not necessarily obvious unless someone points it out to you.

Notes:

• You can switch identities for posting and commenting on any business page, but you can’t do it with personal accounts. You can only post to their Timelines or comment on their posts as yourself, not as a page. This is to prevent businesses from spamming personal accounts, so I’m glad about that!
• This capability is only available for the desktop version of Facebook, not the mobile apps as far as I can tell. There is a setting in the apps that says you can do this, but I’ve tried it with both iOS and Android apps and it didn’t work; I could only post as the page. So I don’t know if it’s an old feature that is no longer available but they forgot to remove it from the menu, or something they’re testing out (and failing at).