The Magic Card Sleeve

Effect:
Magician lets the spectator draw a card freely(no force), and sign it.
The magician puts the card back into the deck, and shuffles the cards.
The magician shows one card on the top of the deck,
but it is not the same card the spectator signed.
This card is put into a clear plastic sleeve,
they can see the face of the card is still not the signed card.
The magician holds the sleeve, then the card slowly and visibly changes into the signed one!!
The card can be removed from the sleeve by spectator and there is nothing else in the sleeve!!
Secret:
Before you start find a normal 3 of hearts (or whatever your sleeve contains) in a pack of cards and put a small dot on the back in the corner and place it on the top of the deck, set the card sleeve to clear (see through). Spread the deck of cards out on the table and ask a spectator to choose any card, this is a free selection.
Ask them to sign the face of the card and place the signed card on the top of the deck thus on top of the 3 of hearts. Now cut the cards as many times as you like this will not disturb the signed card being above the 3 of hearts. Now just go though the cards looking for the small dot you placed on the 3 of hearts and cut the pack so that the signed card is on the top and the 3 with the dot on it is the second card from the top of the deck, stating you have found the signed card.
Now the tricky bit:¬†You will need to do what magicians call a “double lift” check youtube out for tutorials on this but you’re basically lifting 2 cards up but pretending there is only one. So you will be showing the 3 of hearts but hidden behind it is the signed card… you will pretend you have made a mistake by not finding the signed card so place it (them) back on the top of the deck. Now show the sleeve. (a good idea is to wave it over the deck to show it is see though)
Place the top card in the sleeve without showing it (this is the signed card but the audience think this is the 3 of hearts that you showed them earlier) make sure you have the sleeve pressed to show the fake nine of heart showing before you turn the sleeve over. Now simply and slowly hold the sleeve pushing the end to make the most amazing card transformation into the signed card.