You lead the ace of hearts, and partner plays the nine, reverse attitude with suit preference overtones when his attitude is likely to be known, according to the CC. Declarer plays the two of hearts. What would you do now?
If you decide to switch to a spade, partner plays the jack and declarer the king, and now declarer leads the six of hearts. You win with the king, partner playing the ten. Over to you.
Apologies if both hands I posted from today's England v Monaco match are known to you.