In Ragnarok Online your Skills depends on your Jobclass. When you start your journey you are a Novice. When you reach Job Level 10 you can change your job to one of the 1st classes Acolyte, Archer, Magician, Merchant, Swordman or Thief.
When you want something special than you can change to an extended class like Gunslinger, Ninja or TaekWon Kid.
You can become a Super Novice, to become a Super Novice you have to reach BaseLevel 45 and Joblevel 10.

After you change your Class your JobLevel is set back to 1. Now you have to get the minimum Job Level of 40 to change your Jobclass again.
But only Acolyte, Archer, Magician, Merchant, Swordman, Thief and TaekWon Kid can change to a new job class.
Did you reach Baselevel 99 and JobLevel 50 with one of the 2nd Class you can get a rebirth. Only the 2nd class of Acolyte, Archer, Magician, Merchant, Swordman or Thief can get a rebirth.
Now you are a Novice again but you are stronger than the last time.
When you chose your jobclass you can't change to an other to a different Job Class except your 2nd Job Class or Rebirth-Class. That means a Swordman could not change to a Thief or an Acolyte. The Swordman can only change to a Knight or Crusader.

A short discription of a Swordman life in Ragnarok Online:

1. Start as Novice
2. Reach Joblevel 10
3. Chose his 1st Class (Swordsman)
4. Reach Joblevel 40-50
5. Change to the 2nd Class (Knight or Crusader)
6. Reach Baselevel 99 and Joblevel 50
7. Rebirth in Yuno
8. High Novice with Baselevel and Joblevel 1
9. Reach Joblevel 10
10. Change to the same 1st class (High Swordsman)
11. Reach Joblevel 40-50
12. Change to the Rebirth Class (Lord Knight or Paladin)

Basic overview

@LeafRO 2014-2018