When I unlock my AT&T phone does it allow me to remove the AT&T software?

No, you are not required to leave. You can continue using an unlocked phone on ATT. The only thing unlocking does is allow you to use it on another carrier. 

It sounds like I won't even be able to remove the AT&T software from my phone. But that can't be correct. I was under the impression that AT&T has to let me take my phone and leave which would definitely include removing the AT&T software.

So I contacted support and they confirmed that I need to root my phone to remove the software or install a custom rom. A custom rom is probably an unlikely outcome because the AT&T version Note 5 isn't popular enough to warrant such an effort. I'm on Android 6.01 so my only option is to turn this phone off for awhile to wait. I'm leaving the AT&T network because they really did completely screw me over on this purchase. It was 735 dollars for this phone and it is loaded with AT&T bloatware that I haven't used once in over 2 years.

Warning: Do not update your phone if you can help it! The new Androud 6.01 firmwares by AT&T prevent downgrading and there is currently no root methods for N920A on Android 6.01. What I'm saying is AT&T intentionally is breaking the law that allows us to root and flash our phones with different firmware. (but they are so large none of us can take issue with it)

In case anyone doesn't understand this your Note 5 is the same device as any other Note 5 with the same beginning numbers SM-N920.. The A at the end is an indicator of where you are going to take it for being dumb enough to purchase an AT&T Note 5 with their locked down software. (again this is definitely against the spirit of the law, I should be allowed to flash my device + leave at the end of my contract)

@droided

ATT version of the Note 5 is bootloader locked and signed.  You will not be able to root it.  

There is not a single law that says you have the capability to root, flash or unlock a bootloader. You are not allowed to alter the firmware and software of the device. This is in the user agreement.

When you purchase a carrier branded phone, you are bound to the terms of the software. This is why unlocked, unbranded devices exist. This shouldn't be a surprise to anyone because carrier-branded Android devices have existed for almost a decade now. This is nothing new. Phsyical possession of hardware does not grant someone the ability to alter, reverse engineer or modify the software.

Well I don't have any business arguing the law at all.  However, when I purchased the phone along with my wife + inlaws your sales person explained I can unlock my phone then flash a different firmware because it was a chief concern of mine during purchase. We all have the same purchase date, I'm sure you know who I am with all the complaining I've been doing so you can verify that part of my story. But I'm also not here to argue about that either. I'm very unhappy that I have a phone that will have AT&T software on it which upgrades my phone without permission. It resets my choices such as syncing contacts and I always have to turn it back off. So I will get this thing paid off soon then as an only way to get back I will switch carriers.

I obviously had no idea you were leaving your apps on my phone for life when I agreed to pay 735 dollars for this phone and you know it. I get burned, that's the end result. I can't do anything but pay off the phone then try to sell it. I never had any intention of rooting my phone I will just replace it. What I would love to do is downgrade back to the operating system that was on my phone when I agreed to stuff. It's not the same phone the battery doesn't last on Android 6.01 and I can't even count on it unless I have it in ultra power saving mode.

@droided   

There is no way to say this without sounding very insulting, I will apologize now, because there is no way around it.  

If you didn't know a carrier branded phone with lollipop or newer software, especially from Samsung could not be rooted, you had no business ever considering it in the first place.  

The fact the sales person was equally unaware tells you something about how much they know about unlocking.  Most likely had no idea what you meant, just said yes, yes to what ever you wanted to hear.  

Just so there is no mistake....carrier branded phones are not able to be rooted.  You want to play games, you wanted a Nexus.   The Nextbit Robin welcomes custom ROM.  

Yeah unlocking for use on another carrier is something everyone is entitled to do. In fact that IS protected under the law. Removal of the branded software and carrier operating system however is not included in that. 

And it's because too many people back in the day bricked their phones messing with the bootloader and flashing different operating systems only to expect warranty service. Not only that but the variations in hardware among even the same model make it difficult to ensure that everything works properly. Then it all comes to to intellectual property rights and security. 

The FCC states that an unlocked phone is only required to make phone calls on another network. That's it. Voice calls. Data, advanced features and MMS, etc are not ensured to work. This is why the market for unlocked, unbranded devices has grown steadily over the last few years. But on the flipside a carrier can withhold certain features on non-branded devices. Biggest example of this...VOLTE does not work on non-branded devices (handful of exceptions) and may never work.