Ask the person to pass lead back? Hope the person doesn't destroy the league? Leave the league and start a new one?
Like Piper said ask them to pass it back. Sorry but if a person in your league won't pass lead back, maybe you should be looking at who people are inviting into it.
A few years ago there was a glitch that took my lead away and randomly gave it to a leaguemate. Of course it picked my most sarcastic, smart-*** member. He held it over me for bout a week. He thought it was sooooo funny lol. Threatened everyday to disband (though I knew he wouldnt) yeah, good times.
Easiest solution is for them to pass back, harder version would be to form new league. You cannot force them, vote amongst league mates, or even complain enough to DBG about your mistake to get it reversed.
To go along with the consensus here, ask them to pass it back to you. If the person refuses, then as someone else said, "submit to new leader." OR, you might try to submit a trouble ticket for it. The worst they can say is no.
