Guest drunk came to front office ask for his key but he had already had his key, what can you do this case?

provide the duplicate key..................................................

It's don't have to be problem due to the electronic card keys using in21 centuries. If you see that the guest is going to make problem in the front desk he needs to be calm down and sit with guest relation while the reception shift leader will prepare the key and follow it into this system. The professional guest relation better speaking his language will try by the nice way to ask guest to remind where he put the key. If not - block the ok key to issue the new one and by nice smile with assistance of bellman or security to escort him to the room to relax

First I tell to him you already took the key to your room after that if not listen because of his already drunk he forgot no need to panic because of he is our customer I give him to another key and when he is coming normal conditions I will ask him both key.

Politely ask him for his room number or full name so that you may confirm his identity on the system. Kindly hand him the spare key and grant him access with the golden smile you were hired for.

use second key because of the guests condition

Politely ask him to check if the keys are with him. Check for his id and then escort him to his room for further confirmation.

Easy . Confrm again with guest his name and room number  and just make a new key card.If you use an old manual key and you only have one left , escort guest to the room and just open door, take back key . Some units , apply a fee for lost "old manual keys" .

In this case we can just inform the guest politely “ sir let us open door for you” and send one of the male staff with him and open the door for him as we should know our guest.

we cant argue with a drunk guest, or make him realize his mistake, very politely you can escort him to his room, as a master key is available at the reception with the help of the manager on duty. May be the other day we can talk to the guest about the key if needed.

Try to talk to him into checking his keys  if he insists i help him access him room using the spare or artificial intelligence

Nicely escort him to his room with another staff member or security and make sure he is in his room not in someone else room. He might have different key or older key that he thin out is not working to open his room. Check his id