yes, it's possible to change out just the small ring.
If it's stock , it should be a 74BCD 30T chainring and getting a 74BCD 28T shouldn't be all that hard.
The alternative, and a bit easier, is to get a 12-27 rear 9sp cassette, as the stock cassette should be 12-25.
This is your bike, correct?
http://www.bikepedia.com/quickbike/B...=F80&Type=bike