failed nclex rn want to take nclex pn

I'm going to guess that English is not your first language (at least, I'm hoping that's the case based on your post). I mention this because if you are not fluent in English, you are not going to do well on the NCLEX, period.

Putting that aside, I have to tell you that the NCLEX-PN is not something one takes because one has failed the RN exam. Actually, it's pretty insulting to someone who has passed the NCLEX-PN to hear someone who fails the RN exam say "I guess I'll just take THAT test....it's easier...."etc.

If you can't pass the RN exam, you aren't likely to pass the PN one either. What makes you think you would? More productive use of your time would be to find out what you messed up on the RN exam, work on those weak areas, and be better prepared to pass it next time.