How to make Nightfall Pa/De as 2nd Profession

Hii,

Is there any quest to do to aquire them as 2nd profession?

You can probablly just do it from the profession changer in the command post...

Ah thanks... command post

Is there any ways/quests that we can do so that we can change to Pa or De via the " K " Skills n Attributes menu ?

Once you change at the npc you can change from the menu. You can basically unlock switching to any profession from the menu for 500 gold per class.