change second proffession

im a lvl 20 e/ne, where can i change my second pro. to monk?

Senji's Corner or the Crystal Desert.

ok... and where in the crystal desert, i´ve been and checked in outpost and towns and i haven´t found this Q?

You have to do certain quests before the secondary professions are 'unlocked' to that character. These quests are called 'The (insert profession here)'s Path. It's found in one of the outposts - Hero's Audience, Destiny's Gorge, or Seekers Passage. Keep in mind you must be Ascended (Prophecies), or Closer to the Stars (Factions) to do this.

thx will check tihs outposts
u say i must be ascended what is that ( yes i am a noob ) :P

Ascension (click me)

In order to achieve Ascension in Prophecies you have to complete the 3 missions in the Crystal Desert (Elona Reach, Dunes of Despair, Thirsty River) and then head back to Augury Rock and enter the Mesa to defeat your Doppelganger. The ability to change your secondary profession is then unlocked by doing a quest for each secondary profession as mentioned above. The quest to change your secondary to Monk is in Seeker's Passage. These quests will not appear until you have Ascended.