Sometimes you notice something's not right with your creative, or maybe you feel like changing it? 

In Reporting, you can select any entity you wish (Campaign or Ad Set), but you'll have to get down to the Ad level to see the option appear. 

In the Action bar you will see the option to edit your creative, like this: 

If you click here, keep in mind that you will edit the creative for several ads at the same time! 

You'll get back to the Creative Flow's Creative page, with a label mentioning that you're editing your creative! But don't worry, the functions are the same ;)

For Snapchat and Twitter due to limitations on their API, the platform needs to create a new ad when you edit and remove the original one, the result will be similar to what is shown below.