Is there any restrictions to use multiple accounts?

[Viseryn]

I want to change my username on this account.As that is not possible I want to make a new account with the name I need.What happens to my current account if use both accounts in same IP address?

[Flying Hellfish]

Go for it, multi accounts is not against forum rules.

[actmyname]

If you do plan on creating a new account to 'change usernames' then you should proceed with the following very complicated steps to avoid trouble:

Step 1. Abandon this account entirely.
Step 2. Use only the new account.

[LTU_btc]

There are no such restrictions. You can make as many accounts as you want, using same IP address. But it's not recommended to have multiple accounts because it leads to abuse. As actmyname said, after you will create new account - use it one only. And don't even try to join signature campaigns and bounties with multiple accounts - you can get negative trust rating for doing it.