It's common that the audiences you are targeting will change over time so StitcherAds allows you to add/remove users from a datafile custom audience.
Here's an example...
You may be running engagement ads targeted at those not opening your emails. StitcherAds allows you to easily add users who have entered the 'not engaged' audience since it was first set up and remove those who have since engaged. Simply export the data from your email system and follow the steps below.
Edit The Audience
Click on Audiences on the left hand side menu
Select the Audience you wish to update
Select the relevant option to "Add Users" or "Remove Users"
Upload the file
Click on "Save Edits"
As with the original creation we will securely encrypt this data and send it to Facebook for processing. The adjustments should be applied in a couple of hours.
N.B. You can only Add/Remove users from an audience who's type is 'Custom Audience'. Because Website Audiences and Lookalike Audiences are made differently they cannot be adjusted in this way.