I've found the prayer posted by raum215 to be fantastic, I say it three times with my NAP rituals. It can be found here.
http://www.studioarcanis.com/viewtopic.php?f=28&t=6142
This may have been posted before but during some googling of Thee Mighty Arzel, I found this prayer someone has written online. If anybody more experienced would advise against this prayer as part of NAP because of it's mention of other Eastern Angels please just delete this thread.
I'm only posting it because I felt a slight urge and it's seemes positive thus far. It was named Conjuration of the Good Spirits.
O you glorious and benevolent angels, Urzla, Zlar, Larzod, Arzal, who are the four angels of the East, I invocate you, adjure and call you forth to visible apparition in and through the great prevalent and divine name of the Most Holy God Erzla, and by the ineffable and efficacious virtues and power thereof, whereby you are governed and called forth, it being therefore absolutely necessary, pre-ordained, appointed and decreed. Now therefore I do most earnestly intreat and powerfully adjure you, O you benign angels Urzla, Zlar, Larzod, Arzal, in the potent name of your God Erzla to move and appear visibly, and show yourself to me in this crystal stone (or mirror) here before me.
And in and through the same, to transmit your ray to my sight and your voice to my ears that I may audibly hear you and plainly see you and include me in your mysteries wherefore I do most earnestly adjure you, O benevolent and amicable angels, Azla, in the most excellent name of your God, Erzla, and I as a servant of the highest do efficaciously invoke you to appear now perfectly visible to me, O you servants of mercy, come and show yourselves firmly unto me and let me partake of the secret wisdom of your creator. Amen.