Hello, Beth and Heather! I'm Cam, Product Marketing Manager for Social Marketing at Vendasta. Editing active posts through Social Marketing is currently not available, but I have taken this back to the team to look into and include in our upcoming developments. In the meantime, you can go into Social Marketing's Recent Post section and click on the individual social media pages to edit the posts directly from Facebook, GMB, LinkedIn, Instagram, and/or Twitter.
We did notice that Facebook had a bug that didn't allow edits, but that has been fixed. As Beth mentioned, just make sure that you are interacting with the post as the Business Page. You will be able to toggle this on the post beside the share button. If you have any other questions, feel free to reply to this post, or email me at email@example.com. We always value your feedback!