But the new policy means that when a United Kingdom general election is called, the party will halt Brexit without a further public vote.
The leftist parties have been moving closer to demanding Brexit be stopped altogether, with the Liberal Democrats pledging to revoke Article 50 and Remain in the European Union, rejecting the original "People's Vote" - the 2016 referendum - entirely.
As a party which has never won more than 62 seats at an election, the prospect of party leader Jo Swinson forming a government is a long way off, even though british politics is at its most unpredictable juncture in decades.
He said: "The undemocratic thing would be not to implement your manifesto commitments and we are absolutely clear that we want to stop Brexit and the way we will do that in the manifesto is that we will revoke Article 50".
Ms Swinson added: "We have argued that a specific Brexit deal should be put to a people's vote to give clarity".
Prime Minister Johnson wants to call an election, but has so far been blocked by opponents, including the Liberal Democrats, who are desperate to avert a no deal scenario on the leave date of October 31.
He told delegates: "The Tory right who've taken over that party, they like nothing more than to bang on about incarcerating more and more people who break the law but strangely they think there should be a different approach to their law breaking".
While there, he was presented with a "Bo****ks to Brexit" t-shrt.
"I picked up a new t - shirt too!"
British Prime Minister Boris Johnson suffered a fresh blow on Saturday after another member of his governing Conservatives defected to an opposition party seeking to reverse Brexit.
The Streatham MP defected to the anti-Brexit party in June, having walked out of Labour with six other colleagues in February to stand as independents.
Sam Gyimah, a former Tory minister, became the sixth MP to switch allegiance to the party this year and some polling companies predict the Lib Dems could take as much as a fifth of the vote at the next election - up from just 7% in 2017.
He was one of 21 Conservatives who voted against the party to stop a no-deal Brexit.