This is called redirect address , it means you have to put 1 short meta tag to your blog source , before </head> tag :
<meta http-equiv="refresh" content="0;url=http://yournewurl.com"/>
That's it , just replace the red word by your new address then your old blog will redirect to your new site ( include any address and you can use it to redirect all your sub blogs to your mail blog, too).
Save and don't bother about the visitors.Keep thinking about your new address name.
I hope this can help you much.