Changing username is not allowed unless you ask theymos. Changing username is not that too simple, one reason why changing of username is
NOT available is because some people can use it to frauds. For example, you used your account to scam a lot of people, then in order to escape from what you've done, you will attempt to just change your username so that whenever they look (search) for your old username, no result will be found unless if you don't delete all of your recent post where your "scamming thing" happened.
Or (no offense OP), Your're one of those people that I mentioned. Really? you want to change your old accounts name just because it is old? Is that a valid reason? Is it enough? or maybe you're hiding something that's why you didn't use your real account to ask this question. See? there are so many risks with just changing our username. That's why this forum doesn't allow changing usernames.
Like what ean014 said,
why don't you just keep your username cause I think it is already good enough, it will still depend on your post and performance, but like you've said you have another account right? much better to just use your old account.
Changing username is not too necessary, quality of posts is the most important of all
plus contribution to the forum. And yeah, one more thing Mr. OP, why don't you use your old account instead?
Something wrong?
I thought that having a Legendary Rank means you have the option to change your Username. Thats what I know. 50 BTC is so much.
Yeah there's no such thing as "Changing username for free" even Legendary Members have to pay 50BTC for it. It's because there are some risks.