Is it possible to change a USA F-1 visa for B -1/B-2 visa because of a change of interest?
In principle, you can change your status, but you won't actually get a new visa. You'll need to file form I-539, Application To Extend/Change Nonimmigrant Status: http://www.uscis.gov/i-539.
This assumes you are already in the US, as Karlson point out in a comment to your question. If you are not in the US, you will probably have to file a new application. Ask at the consulate. They will be able to tell you. Surely this has happened before.