Update: I've leaved the league with old team. So now it is ok.
P.S. Also I've found out in FPL Help that "Unlimited transfers can be made at no cost until your first deadline.". So the answer for my question "Can I change the whole team?" is "Yes, you can do it without any problems until the first deadline" :)
I even can't see any button to transfer players or edit team composition. I think that I will create another account there and join your league with another team...
I'm afraid you'll have to use the wildcard for that else it will cost a penalty in points (-4 per player).
I've created a new team with name "The Hateful Eleven" (manager name Art Z).
Please delete the old one "THE (old)" (manager name Art Z).
Roger that.
Thank you!
Update: I've leaved the league with old team. So now it is ok.
P.S. Also I've found out in FPL Help that "Unlimited transfers can be made at no cost until your first deadline.". So the answer for my question "Can I change the whole team?" is "Yes, you can do it without any problems until the first deadline" :)
I even can't see any button to transfer players or edit team composition. I think that I will create another account there and join your league with another team...