Well, maybe you're right. I'll just say it's beyond -my- abilities anyway :)

Ok, I filled in city pairs to make it easier on you guys. I never thought AAA-BBB would be so tough for the likes of JonNYC to understand :)

I currently have a ticket booked through AA from ORD-FCO-LHR where FCO is a stopover and FCO-LHR is on BA. Call this Ticket 1.
I also have on a separate ticket booked through AA LHR-CLT-MIA all on AA flights departing the day after flying FCO-LHR. I am already going to be throwing away CLT-MIA. Call this Ticket 2.
I want to change FCO-LHR to the next day due to a friend meeting up with me in FCO. The change fee alone on Ticket 1 is more than the cost of booking a separate ticket for FCO-LHR on a different airline, so I want to just throw away FCO-LHR on Ticket 1 and book the other ticket.

​​​1. Should I be concerned about AA noticing me throwing away FCO-LHR on Ticket 1 and then the next day also throwing away CLT-MIA on Ticket 2?

Additionally, after taking the trip above, I also have a ticket booked through AA in the near future from ORD-CDG-HEL-CDG-ORD where I only plan on only flying ORD-CDG (the RT to HEL was way cheaper than just a OW or a RT to CDG). CDG-HEL-CDG is on AY. Call this Ticket 3.
I then have a separate award ticket CDG-ORD ticket that departs after my thrown away segments in Ticket 3. Call this Ticket 4

2. Should I be concerned about AA cancelling Ticket 4 if I throwaway 3/4 segments on Ticket 3?

3. Should I also be concerned about AA noticing a pattern after doing throwaway ticketing on 3 tickets within 2 months and twice in 2 days? I'm mostly concerned about throwing away segments 2 days in a row. These trips will be the first time I have ever thrown away any segments.

Personally, I think you should reconsider. IMvHO, that's a lot of manipulation and machination in a short period of time.

Are you just concerned about the addition of throwing away FCO-LHR a day before CLT-MIA?

I've already booked and plan on throwing away CLT-MIA and then 6 weeks later throwing away CDG-HEL-CDG-ORD after only flying ORD-CDG. Those 2 being over a month apart and on different routes didn't initially concern me.

Standard advice is still correct; chances of getting in trouble over all this = very, very low. That said, you say it's your first time doing all this and the law of unintended consequences tells me to tell you, is it all worth it? Or maybe just do as you see fit this time and try and see how it all works out.

HGF why didnt you simply PM JonNYC or whomever with all the specifics? Now that you got your answer why havent you edited out all the actual flight info?

Because that isn't my actual flight info. I just made it up.

This is the best advice. Take it or not.

It really does make it easier to follow with real cities... even if they are fake real cities.

My fake real city scenario:

SFO-PHX-NRT-LAX-PHX-SFO Flew SFO-NRT segments but travel plans changed and only want to make it to LAX instead of doing PHX-SFO segments... Will that be a problem?

Not unless you check bags.

Even checking bags won't be a problem since you'll have to collect any baggage after NRT-LAX for customs. No problems with this one whatsoever.

Thank you. I just have an event to attend that's closer to LAX than SFO and so it makes more sense for me to just do that... But I was worried that AA might penalize me with something else like my other planned flights or award tickets.

Maybe on the day of travel you can notify AA so that they don't think you are pulling a fast one. They would appreciate the chance for revenue/logistical planning, etc. And you stay on their good side. If you don't skip regularly, they will be ok with it.

Is this an award ticket, or a cash ticket? If an award ticket, you can -- and should -- call AA and ask for the LAX-PHX-SFO segments to be lopped off. This will protect you in the event of IRROPS, to ensure that you get re-routed to LAX, not SFO.

Cash ticket.