Conference delegate Steve Arloff, from Bradford West Labour Party, said Labour MPs should not assume they have "some God-given right to be selected unopposed, expecting it to be a job for life".
As Labour's conference officially begins in Liverpool, a march of MPs, MEPs, union leaders and activists will attempt to put pressure on the party to throw its weight behind a second referendum.
Labour party members who express anti-Semitic views should visit Auschwitz, an MP embroiled in a row with her own constituents has said.
The opposition leader said he believes the best way to resolve the current Brexit deadlock is a general election, but he would support another public vote if party members call for one.
He told Sophy Ridge on Sunday: "It seems to me inconceivable that if the Labour Party conference decides that it wants a manifesto pledge on a people's vote that we would defy that decision".
More than 100 local Labour associations have submitted motions to the conference, which starts Sunday, urging a "People's Vote" - a new referendum - with a choice between leaving on terms agreed by the government or staying in the EU.
It is not clear where Theresa May goes next, after the drubbing her Chequers proposals received at the European Union summit in Salzburg, but when she says it is a choice between her deal (bravely assuming it is not already a dead parrot) and no deal, Labour would beg to differ.
Even in the North and Midlands, where many Labour constituencies voted Leave in 2016, there was overwhelming support - 86% and 88% respectively - for a second vote.
Jose Mourinho: 'Nuno Espirito Santo deserves his chance in Premier League'
The Chile worldwide is yet to score in four games this season and has managed just three in 22 games since arriving from Arsenal. That comes from training every day, you've got to show the manager that you want (to play).
With the United Kingdom and the European Union at an impasse in divorce talks, many Labour members think the left-of-center opposition party has the power - and a duty - to force a new referendum that could reverse Britain's decision to leave the 28-nation bloc.
One of these advisors said during a telephone call: "What are you doing in November - because I think we are going to need an election".
"He's got as much back bone as a jelly fish!" he said.
Mr Watson told The Observer: "Jeremy and I were elected in 2015 to give the Labour Party back to its members".
He said: 'A new poll shows 86% of Labour party members want the British people to be given a final say on the UK's future relationship with Europe.
But shadow chancellor John McDonnell warned on Saturday that a second referendum could stoke racial tensions and far-right populism.
He said: 'Our preference is a general election and then we can negotiate our future relationships with the EU. "The question I think that has to be answered now by the government, by the European Union leaders, is what room for movement is there, how do we move on from where we ended up last week?"
"But I would look at what the question is on offer and I would want to know what the deal is that comes out of the negotiations, if that happens", he added. We are not happy with it and we would vote against it.