Allan was handed a red card in Everton's 1-0 win over Newcastle United thanks to his foot being off the ground when he tackled Allan Saint-Maximin.
The midfielder was initially given a yellow for the incident, with the Magpies substitute looking to hit the Blues on the counter attack with spaces opening up in the defence.
The Brazilian took the opportunity in the middle of the park to bring down the winger as he attempted to burst forwards, conceding a foul in the process.
However, after on-field official Craig Pawson had given a yellow card for the offence, he was then advised to look at his pitch-side monitor by the VAR.
VERDICT: What Alex Iwobi did after magical goal proves what Everton have not had in a long time
ANALYSIS: VAR truth emerges as Bill Kenwright message rewarded
After that, Allan was dismissed - and the reason behind that decision can now be revealed.
It is understood that the VAR advised Pawson to review his decision as it was deemed Allan was off the ground and not in control when he made the tackle on Saint-Maximin.
Therefore, it is believed that he endangered his opponent while committing the foul.
At the time of writing, it's not yet clear if Everton will appeal the decision, although the ECHO understands they are considering that action.
Manager Frank Lampard was adamant that his player should not have been sent off following Thursday's game.
He told his post-match press conference: "Well it's not a red card. Alan Shearer, Mr Newcastle, just said it.
"The frustrating thing for us we had, in my opinion, the most blatant one against Man City - the referee didn't see it, VAR got it wrong and we get an apology.
"This one the referee sees it, he delivers the correct verdict of a yellow card and VAR somehow changes it.
"Did you seriously endanger a player for kicking him on the foot? That's football.
"It's a yellow, yes. It's a strong yellow, yes. Did it warrant an overturn? No."
