Select your ad account from the Choose Ad Account dropdown
A list of all the Lookalike Audiences for that ad account will be displayed - you can use the search bar to find a specific audience in the list.
If you wish to remove a Lookalike Audience from your list, simply hit the red dustbin button next to the audience.
You'll be presented with a warning to confirm the deletion, hit Delete It! to remove the audience permanently, or Cancel to return to the list.