Both of domains are yours ? If yes than you can change it by moving.
My answer;
Before everything , You have to make us to sure about if both domain are yours.If yes than you have to ask your hosting provider for changin hosting for new domain ( generally they dont accept and you have to buy new web hosting for new domain.)
If you get a new web hosting for new web hosting than take a look at this post of Scott.
You will see ( 4- Back up the database from the old site. )
this bacup will be like oldsite.sql and open this with like Notepad++ .After opening use CTRL+H and write old domain name http://bdtips.us , change with http://bdtip.com and click to replace all.After that save it as newsite.sql and you can continue from 5 one of scott post
