Alternative username?

[AtiaoftheJulii]

I assume I am missing something basic here, but how does one use an alternative username? Do you already have to be registered under that name? I tried typing in a random string of letters, and it told me that name didn't belong to me, but I can't find any simple instructions!

Hello - are you on the mobile site? If so, yes, you can only use a name you've already assigned to yourself via the usual namechanging procedure (in 'My account'). Does that make sense?

Ah, yes, I was only reading that bit as a permanent namechange, not that you could swap back and forth. Thanks!