According to the Associated Press, the shadow chancellor said that "we argued for "remain" in the past but we lost that vote so we have to respect that".
Corbyn appeared on the BB'C's Andrew Marr Show this morning and said he hoped there would be a general election soon.
John McDonnell admitted the motion Labour Party members agreed on Sunday keeps the option of a second Brexit referendum on the table.
Corbyn wanted his conference to be an opportunity to sell his alternative vision for Britain's economy, pressing his argument for the renationalization of rail, mail and utilities, and to rally the party for a possible early election.
Labour activists have waved through sweeping changes to the party rulebook that could trigger waves of deselection of Jeremy Corbyn's critics.
He said: 'Our preference is a general election and then we can negotiate our future relationships with the EU.
Several members from Labour branches voiced their opposition to the plan as they suggested it did not go far enough, with many supporting mandatory open selection contests for all MPs before every election.
The result is far from a commitment from the leadership to back a second referendum, but nevertheless it represents a victory for campaigners and indicates Mr Corbyn is prepared to listen to party members. The referendum "absolutely must include the right to remain in the EU", he said.
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".
All other changes which emerged from a party review of rules, including new powers for Scottish and Welsh conferences to determine how NEC representatives from the Scottish and Welsh parties are chosen and the creation of a disability place on the committee, were approved by at least 90% of those who voted. "We must back it if Labour members want it", he told The Observer newspaper.
In a hint that the option of remaining in the European Union might not be on the table in any future referendum, he said the form of the question would be decided by Parliament but "it will be about whether you accept the deal or not, or whether you send people back to negotiate a proper deal".
"If we can't get a general election, we've kept the option of People's Vote on the table and that's what we'll go for, but I'd much prefer a general election".
But, he added, he would advise Mr Umunna, to "get behind the leadership" and the party's policies "and help us work towards a Labour government".