England is a crazy lawless anachronistic place.
If May loses the Queen dissolves Parliament.
New election.
Hello Liberals?
No, the Conservatives would still have the numbers. They would just have to pick a new leader who would then become PM.
If May loses the Queen may appoint a new First Minister, who must be able to form a government that commands the confidence of the House of Commons.
Usually, but not always, that person is the elected leader of the majority party, if there is a majority party.
Right now, the majority is a coalition of two parties, and the junior member of the coalition agreed to serve under Theresa May.
Without a majority party, the Queen has a tiny bit more freedom - she could, I suppose, dissolve Parliament without the consent of the coalition since they have f***ed things up so badly, and try to have an election that would yield a stable majority.
The problem is that, odds are an election now would put Jeremy Corbyn in #10, and his first move might be to send the moving vans to the Palace to see of the Germans for good and all.
Interesting times.