It would be very similar to the way you would summon any other magical creature. If you know how to do it for a dragon, fairy, or angel then you will be able to figure out how to summon a phoenix by researching them ;)
I partially agree with Kts, but only because I haven't tried summoning a fairy or any other magical creature before with the exception of dragons. I don't consider Angels magical, that's the only part I disagree with. For Angels, like Spirits, you can simply ask and meditate. For Dragons I did the same, but since I had the benefit of having a Dragon Spirit Guide I'm not sure if it's the same for all Dragons. Might just be like that for Dragon Spirits which would be classified as Spirits.
PHOENIX is a great Duke and appears at first in the form of the bird Phoenix with a childs voice. Before he will be still before the conjurer, he will sing many sweet melodies. Then the conjurer and companions must beware that he give no ear to the melody, but must bid him take human form. Then will he speak marvellously of all wonderful sciences. He is an excellent poet, obedient and governs twenty legions. Phoenix must be kept focused on the task at hand and should never be allowed to wander without the circle.
Draw a circle upon the ground and recite the following invocation aloud: I conjure thee Phoenix, in the names of Baell, Paimon and Zagan and by their virtues and powers I charge thee Phoenix, that thou shalt not depart out of my sight, nor yet to alter thy bodily shape, that thou art appeared in, nor any power shalt thou have of our bodies or souls, earthly or ghostly, but to be obedient to me, and to the words of my conjuration, that be written in this book. I conjure thee Phoenix, by all thrones, dominations, principats, potestats and virtutes, and by their virtues and powers. I conjure and charge, bind and constrain thee Phoenix, by all the words aforesaid, and by their virtues, that thou be obedient unto me, and to come and appear visible unto me, and that in all days, hours, and minutes, wheresoever I be, being called by the virtue of the highest, thou shalt look ready to appear unto me, and to give me good counsel, to give to me thy melodies and poetry, and in all other things my will quickly to be fulfilled: I charge thee upon pain of everlasting condemnation, Fiat, fiat, fiat, Amen. When Phoenix appears, stay quiet and listen but if he should linger long on one single note or word, he must be distracted and redirected with a question. When the engagement is complete, dismiss Phoenix with the Dismissal of the Spirit.
"When the engagement is complete, dismiss Phoenix with the Dismissal of the Spirit."
Dismiss? Who's dismissing who? The phoenix would be the one dismissing you.
I will not wish you luck.
"I conjure thee Phoenix, by all thrones, dominations, principats, potestats and virtutes, and by their virtues and powers. I conjure and charge, bind and constrain thee Phoenix, by all the words aforesaid, and by their virtues, that thou be obedient unto me"
Do not even try, even if you manage to get a baby phoenix to go to you, be prepared to die for trying to bind and constrain it. You're freaking crazy if you want to mess with a phoenix at your level of power (I can tell by 1. Instinct 2. You're asking if a spell works).