Switching SE Accounts?

Trying to give a friend my XI account, but I tied it to my SE-Account waaaay back in 2011, and I currently use that for XIV. I don't want to pay for both services or handle some fanagled payment system that he pays me back $13 every month.
Is there a way I can transfer the XI portion over to his SE-Account, or even a way to split payment method?
The Account management pages just has "Options List" (What you pay for) and "Cancel Service", and "Transfer ID" is just the thing I did back in 2011.

So basically the only option is to pay it all myself and have him pay me back $13? Great~~~~

I did a one-month reactivation so he could use my ~3years worth of banked-up voidstones for some event, so he's got that already.
Super annoying yeah...
I did notice when you try to buy Crysta you have to input your payment info (read: doesnt automatically use the stored card info), so if I could find a way to set Crysta on XI but keep the card on XIV, he could pay it that way?
The language on "change payment method" is kinda odd too as it makes it seem like it refers to just XI AND both XI/XIV at the same time... If its possible to put a different card on each game's fee, that'd be the optimal solution, but it's sadly not what it seems will happen.

So it IS possible to setup Crysta on XI and keep my normal card on XIV? Or would I have to start buying Crysta for XIV as well?

I only ever had one XI char which will deactivate on the 11th.

Ok yeah that's what I was talking about with the weird wording in the billing language on the XI-side.

Just set XI up on Crysta, and XIV is still showing as credit/debit card on the Subscription list.
So now the question is if XI and XIV can be setup to auto-bill on separate cards altogether, but this works for now since they won't have to pay for the account more than they use it.

Off topic: Christ I missed this Miku avatar... :')

Yes.