Secondary profession

A secondary profession allows a character to learn and equip all of that profession's skills (including elites), and all attributes except the primary attribute. A character is still limited to the armor and runes of the primary profession. Taking a secondary profession doesn't affect character appearance.

The main purpose of a secondary profession is to broaden a character's range of skills. When choosing a secondary profession, it is best to pick the profession, attributes and skills that best complement your character and your playing style. For example: Fire Magic would probably be a poor choice for a warrior. Warriors have only 20 base energy points and two pips of regeneration but many Fire skills cost 10-25 energy points. On the other hand, Earth Magic has several useful skills that cost only 5 or 10 energy or are centered around the caster.

There are no definitive secondary professions for a given primary profession. It's all a matter of playing style, and what players feel their character is lacking in.

PvP characters start without a secondary profession. On the K menu they can choose any profession they want for free any number of times they want.

PvE Tyrian characters choose a secondary profession during the Pre-Searing quest "A Second Profession," which must be completed before moving on to Post-Searing.

Canthan characters can try out and choose secondary professions after the quest An Audience with Master Togo. Getting a secondary profession is necessary to get to the first mission.

Elonian characters must reach level five before they can accept a second profession. Once they reach level five, they receive a quest and may talk to the experts to try out skills from different professions. Elonians are able to choose their secondary after talking to at least one expert.

How to change your secondary profession
It is possible to change your character's secondary profession after becoming Ascended or Weh no Su, or must have completed the quest Hunted!. Depending on the campaign, you will first need to unlock the ability to switch to a particular profession for your character. In Prophecies, you need to complete a quest. For Factions and Nightfall, you will need to pay a one-time fee. Once so unlocked, you can switch amongst your unlocked secondary professions easily via the attributes panel (default shortcut "K").

Prior to the update that made it easier to switch secondary professions, characters had to go talk to profession changers. There's at least one in each campaign. There is also one in the Great Temple of Balthazar.

Prophecies
Once a character has Ascended, speak with Vanyi in Droknar's Forge, and she will direct you to visit the 3 outposts in the Crystal Desert. These outposts are the collective home of six quest-giving NPCs, each of whom has one quest to offer:
 * The Elementalist's Path
 * The Mesmer's Path
 * The Monk's Path
 * The Necromancer's Path
 * The Ranger's Path
 * The Warrior's Path

You will unlock the ability to change to each profession by completing its respective quest. Once a quest has been completed, you may learn or relearn that profession simply by talking to the quest-giver (you cannot repeat the quests). You will never receive the quest pertaining to your primary profession, as it can never be changed. You will also not receive the quest for your original secondary profession -- the ability to relearn it is automatically "unlocked".

Factions
In Guild Wars Factions, one has to achieve the status of Weh no Su by completing Nahpui Quarter in order to change secondary professions. After completing the mission, the player will be in Senji's Corner. Talking to Senji and giving him 500 gold will change your secondary profession to the one you desired. Changing back is free of charge. Senji does not require a quest to change your secondary profession. Senji does not charge for the initial profession change from him if your character has done that Prophecies profession change quest.

Nightfall
In Guild Wars Nightfall, the quest Hunted! must be completed in order to change secondary professions. At this point characters can either map travel to the Battle Isles and talk to the Profession Changer at the Great Temple of Balthazar, or they can talk to Zuwarah, the profession changer at the Command Post just north of the Sunspear Sanctuary (500g cost to unlock a new secondary profession at either location).

Switching from one secondary profession to another
If you decide to later change back to any previous secondary profession that your character held, the skills that were earned for that profession will be restored. Any skills that are unlocked by your character will remain unlocked for PvP. You will not lose your Ranger pet should you change away from a Ranger; the pet is restored when you switch back to Ranger as your secondary profession.

Once you have changed your secondary profession, all profession-specific quests that reward skills for your new secondary profession will be made available to you. You can then backtrack and complete these quests to learn free skills. Universal skill quests do not reset, so if you already completed some, any skill rewards that they would have offered for your new profession can no longer be obtained in this manner -- you will have to purchase or capture those skills.

If you are aiming towards the max level for Skill Hunter, you'll need to be able to change your secondary profession to all professions excluding your primary. If you have captured all elite skills for only two of the six Core professions, you would only capture 69, 70 or 71 elites (Warrior has 36 elites, Mesmer has 34 and all the others have 35 each), which is not enough for the first Skill Hunter level (90 captured elite skills is required).