Grand Master Pabris:
To become a Rogue, you need the appropriate level and token. Your level should be at least 20 to be qualified to change profession. You also need a token to prove that you passed the Test of the Rogue, as well as an appropriate level.
I am satisfied with your level, but it seems like you did not pass 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 to take the test. He is at the entrance to the harbor on the west side of the village. To become a Rogue, pass his test and bring back his Recommendation.