Weapon Exchange with SA?

I got a few weapons I want to exchange with Mammon, however, they already have SA on them. I understand that SA cannot be exchanged along with the weapon, but I am just wondering if I need to remove the SA first before the exchange is allowed or can I just exchange while in the process the SA will be removed automatically.

You can remove the SA for free at the blacksmith of mammon. Or black marketeer of mammon for a fee.

What? ****. And here I am always spending AA removing them with the Black Marketeer before I swap/ upgrade.

I did not know that too, and paid for it gah ...