Requirements: There are only two prerequisites to take the quest to be reborn:

Level 120+ (or level 110+ for water taoists).
Celestial Stone (clean water, phoenix gem, dragon gem, moon gem, rainbow gem, violet gem, fury gem, kylin gem).

Note: Water Lords on the adventure sometimes drop clean water. Gems however (one of each type as stated above), must be gathered by other means.

Walkthrough: First, prepare 7 normal gems and a bottle of clean water. You can dig gems from the various Mine Caves in each major city map, and get Clean Water from a monster known as a water lord in the Adventure Islands.
  Take them to the Celestine (Twin City 365,92). He'll use your gems and clean water to make a magic celestial stone for you.
  Take the Celestial Stone to Eternity (Market 298,217), speak to Eternity and you can be reborn.

i. You can select a new profession and select the size/model of your character.
ii. You may choose to get a super gem or randomly add the blessed attribute to one of your equipped items.