Can you resign the game before it even starts, or can you resign after the first move of the game is played?
Strictly speaking you can resign at any time the game is in progress. The practical implication of this is that, unless there is no series of legal moves whereby your opponent can deliver checkmate, you lose and your opponent wins.
For rating purposes the game is not viewed as "started" until each side has played one move. Hence the earliest you can resign is after one move.
If you just don't want to play the game the best course of action is to tell the arbiter beforehand that you are withdrawing. You can say "for personal reasons" and you don't have to go into detail. If you want to continue in the tournament, just not play that game, then again go to the arbiter and tell them you had a phone call from home, you are very sorry, but you have to go back to sort it out or just take some time out to sort it out if you live a long way away.
The next best course of action would be to phone default. Have your phone with you and switched on and arrange for a friend to call you just after the game starts.
All other courses of action, including resigning after one move, have bad consequences for you.
- If you play one move and resign then you will come under suspicion of collusion with your opponent. Depending on how strict the organisers are you may end up anywhere from being thrown out of the tournament to banned for life from that tournament in future years.
- You could just not turn up for the game.The question will be asked, "Why didn't you tell the arbiter?" This could affect your entry to the tournament in future years or any tournament where the same organisers or arbiters are involved.