Mrs May made a statement to MPs about Brexit on Tuesday, amid the threat of a revolt by Remain-supporting ministers.
The PM has promised MPs a meaningful vote on her Brexit deal by 12 March.
But Labour leader Jeremy Corbyn accused the prime minister of another "grotesquely reckless" Brexit delay.
The prime minister said she will put her withdrawal agreement - including any changes she has agreed with the EU - to a meaningful vote by 12 March.
If that fails, MPs will be offered two separate votes: