Is there a way to completely take that off the audio track
My guess is no. The Noise Reduction tools need a second or two of “pure noise” as a sample. Noise by itself with no other sounds. Any of the other sound management tools might delete the vent noise, but will also destroy musical tones that happen to match the vent sounds.
If you do this all the time, scope out a different seat further from the vents. Best is get the venue to give you a copy of the House Mix. If you’re rolling in bucks, you can bring a shotgun microphone much less likely to pick up anything not in front of it.
Audience captures fail a lot more than they succeed. The microphone overloads, the hall echo is terrible and the man next to you starts opening a bag of chips.
Koz