If you have previously recommended this thread, you should see a tick / check mark on the recommend button. Click the tick to undo the recommendation (the tick may appear to change to a cross as you do this.) If you added a comment with your recommendation, you will need to delete that from your facebook wall separately.
Desperately need to update my playlist, seem to be stuck 10 years ago with things like Norah jones and Eva Cassidy. Hopelessly out of touch with current stuff, so hoping you all can recommend me some new stuff along these lines!