Grand Master Rains:
To become a Rogue, you need the appropriate level and token. Your level must be at least 20 to qualify to change profession. You also need a token to prove you have passed the Test of the Rogue, as well.
I am satisfied with your level, but it seems that you have not passed the Test of the Rogue. You can only be accepted as a true Rogue when you pass the test. Seek Captain Bezique of the village of Gludin. Go straight west to get to the village of Gludin. Captain Bezique is at the western entrance of the village. To become a Rogue, pass his test and bring back his Recommendation.