Being autistic, I was very reluctant to surrender or admit defeat if I ever lost an argument and I usually had to turn disagreements into massive wars as a child. I'm older and wiser now, yet still have autism.
However, the argument that autistics can't learn is nonsense, and while it took a fair amount of pride swallowing, here's some tips (especially for fellow autistics) on how to conclude arguments and disagreements effectively.
1. Just be happy knowing you're right - You can't win every argument, even when all the facts are on your side, because some people cannot be reasoned with. Trust me, I've tried, doesn't work out 100% because humans are irrational sometimes and not always given to being reasonable, so expecting reason to triumph all the time is a pipe dream, but even if the other party isn't amenable to reason, just be content knowing you aren't the irrational jackass.
2. Be willing to admit you are wrong, or at least the possibility you might be - Even if you aren't, or your ego won't allow you to believe it, at least admit the other side might possibly have a point if you aren't willing to fall on your sword completely. Even if you don't believe it, conceding the other side might have a point has two advantages:
a. If you are wrong, you admitted the possibility up front and don't look like an idiot asshole later by doubling down on your own errors.
b If you are right, you can at least say you allowed the possibility you were wrong, so you don't look like a smug asshole when your side of the story is vindicated.
3. Know when to leave the argument - This is not the same as surrendering an argument. If you are willing to leave before getting yourself boxed into a corner, you can, if you do so at the right time, come back to the argument later when you have a stronger case to argue and possibly prevail later. Getting your ass metaphorically kicked (or if you piss off the other party too much, literally) by arguing when you aren't prepared only makes you look like a jackass and will make you suffer at the same time, either in terms of ego or your physical well being, depending on the rationality of the party you are arguing with.
4. If the other side is being unreasonable, YOU MUST REMAIN REASONABLE - If the party you are arguing decides to be irrational and hurls insults when they start losing the argument, remain reasonable and ignore their attempt to anger and bait you. By doing so, you do not give them any ground to gain a moral victory even if they can't get an intellectual one, not to mention anyone else witnessing the argument will think better of you for not sinking to the level of the unreasonable party.
5. Always show civility, even if the other party never does - The first side to be a douchebag loses in some way, even if only in the moral sense, and even if you are dead wrong, the fact you can argue while not being a prick about it means that you might be able to reargue your case with the same party at a later date, and even if you can't, others party to the argument will be more inclined to either side with you or not help out your opponent if you are the one consistently showing grace and humanity.