I did this last year by accident. The account is with TD Ameritrade. They had a one page form, which I submitted with instructions to move the assets [those purchased with the excess contribution or with dividends from that contribution] into a regular taxable investment account. No sale, no fees, no bad tax consequences (just avoiding penalties for over-contributing, which was the point.)
The only caveat is that I had to get the excess contribution out of the IRA before I filed taxes for that year. (In my case, I over-contributed in 2013, removed the excess in January 2014, filed taxes as normal after that, and all was well.)
I was not educated enough at the time to know that there even was an income max for utilizing a Roth, not to mention the possibility of reducing MAGI. So much I have learned on these forums in such a short time!