Hello @UKSitter and yes, once you have saved (hearted) particular listings, you can un-save them.
On the app
Go to Favourites
You’ll be able to scroll through the listings you’ve “hearted” and remove any you no longer want by clicking again on the heart.
On the website
From the dropdown menu select favourites
You’ll see the messages for those listings you have favourited
Select the one you want to remove and go to the listing
Remove the heart by clicking on it
I’ve always found the app to be easier for this process if you’ve got lots of “hearted” listings.
Hope that help but if there’s anything I’ve missed just ask