Is it possible to set an encryption password different than lock screen pin? I set up phone encryption using a numeric password. android 4.4.4 on One plus one (Cyanogenmod 11S).

now on the lock screen I'm asked for the same numeric password (but instead of a text input field, an on-screen  numeric pad is shown). 

I would like to understand :


is it possible to set a different PIN for lock screen than the one I set before encrypting the phone? (without changing the current encryption password) 
is it possible to change encryption password without wiping phone memory? 


Thanks in advance
Please, keep in mind -- one problem, one question here. Two questions in one post is a bad idea.

Now:


first question: take a look here or here or in many other places,
second question: no, encryption is irreversible!


Once applied the only way to disable it / change password is to do factory reset (loosing all data / wiping phone memory -- as you write) and perform another phone encryption after that.