how to use set_select on a form to show the old value?

You have error in request set_select('request', $booking->status) Why 'request'?

You're right, typo while retyping the code, I corrected it on the post.

For you're other suggestion to change the way I am calling the options.. I have just 3 of them, they work already for creating bookings in my code, so I was expecting to use them with the set_value when I edit the booking following the example that should work no?