Originally Posted by
Acquiesce of Telara
Sen,
When you level in most MMOs, quests lose their XP value as you get higher and higher level. A level 10 quest at level 10 is worth, say, 200xp. If you do the level 10 quest at level 20, you won't get XP because there's no challenge. You outleveled and outgeared the quest.
Mentoring allows you to do low level quests for their full value because your gear, stats and level are altered to (almost) match what was expected of you.
If you right click your portrait at your normal level, there should be 4 option: PvP, Reset Instances, Dungeon Difficulty, Public Group, and Set Ascended Mentor Level. Choosing Set Ascended Mentor Level, you can choose anything from 10 to [your max level - 5]. When you're leveled down, there's a 5th option when you right click: Clear Ascended Mentor Level. That'll pop you back to 19, or 20, or whatever level you are now.
If you can't see Clear Ascended Mentor level, I'm guessing you must be in combat or something.