Allowed de-level without losing skill

I am creating a warlord for cata farming im planning to level it beyond 52 and reroll to the same level; 52 for low lvl catas/nercos - i am playing on an official server [SEA] - WHAT IS THE ALLOWED DE-LEVEL OR GAP FROM YOUR PREVIOUS HIGHEST LEVEL TO YOUR TARGET DE-LEVEL WHICH WILL NOT COST YOU ANY SKILL LOSS?

The GM said that if i delevel too much, most of my skills will be equalized to my current level.

When i asked what is the acceptable difference:
The GM simply answered that "we cannot divulge such information".

TYVM!

as far i know it should fall when u fall bellow the level with new skills like - u have lvl 40 and delevel to 39,u should lose your lvl 40 skills ... but im not 100 % sure

Their seems to be a limit more than 1, but the GMs' are now willing to share info. ><

By gain your lvl back after a dlvl you will take the skills also.
Some passive skills dosen't change (weapon and armor mastery) by dlvl but armor S,A,B,C expertise it change or some active skills.
In some servers they have a special NPC for instant dlvl, in that case you entirely LOSE the previously gained skills.