Posting on Facebook as my business page

For those of you who have a photography business page on Facebook (aside from a personal page), is there still a way to reply to posts as your business? I used to be able to do it but lately I can only reply as myself, not as my photography business. I am talking about replying to posts on other pages, not on my own business page. I looked up online how to do it and found instructions, but the option they list for changing (clicking on my icon) does not show at all for me.