http://www.sythe.org/name-sales/1506579-what-really-makes-rare-name-rare-how-transfer-name.html In here shows how you can do it, but there are other ways you can do it for example getting a name banned and having it pre-typed before switching (good idea if you want it on a main account, rare occasions jagex will pick a name for you.) it's also very risky though.
You have complete control over when the name drops with the 1 month method. If it's a very rare name it'll be sought after no matter how you're transferring it, so it's best to consult someone familiar with the process if you haven't done it before. If you're transferring something that's semi-rare but not really worth sniping you can probably get away with taking no special precautions and transferring it using the method listed there
This name is very rare and would be much sought after, how soon can I transfer the name to another account and why does the guide advise to wait a few days?
Well after the second change of course.. If you're transferring "Hello", you'd change the name to "Hello123" and after 28 days change it to "Hello456".. As soon as it's changed to "Hello456", "Hello" becomes available. That's what I meant above, the way I said it was a little strange

