The prime minister said she will put her withdrawal agreement - including any changes she has agreed with the EU - to a meaningful vote on 12 March.
If that fails, MPs will be offered two separate votes:
One, on 13 March, on whether MPs support a no-deal Brexit - so the UK would "only leave without a deal on 29 March if there is explicit consent in the House for that outcome"
If that fails, then MPs will get a vote the following day on requesting an extension to the two-year Article 50 negotiation process to delay EU withdrawal beyond 29 March
https://www.bbc.com/news/uk-politics-47373996