Eu referendum whats your vote

At the Labour conference, the UNITE man said it all: " The vote on the final agreement is just that, a decision on the agreement, NOT a vote to accept or leave". He’s got his head on I have to say.
I read also that MORE Labour constituencies voted to LEAVE the EU in the great referendum (70%). Those in the north, north east, Wales etc. I wonder how those elected Labour members of parliament in those said constituencies aim to uphold their electorates votes…to leave?