turn vs change form

turn is a noun but change form is not a noun.

Word	Noun	Adjective	Verb	Adverb
turn	Yes	No	Yes	No
change form	No	No	Yes	No

As verbs, change form is a hypernym of turn; that is, change form is a word with a broader meaning than turn:

Other hypernyms of turn include change shape, deform.

turn (noun)	change form (noun)
the act of changing or reversing the direction of the course
the act of turning away or in the opposite direction
taking a short walk out and back
a favor for someone
(game) the activity of doing something in an agreed succession
turning or twisting around (in place)
a short performance that is part of a longer program
a movement in a new direction
an unforeseen development
a circular segment of a curve
(sports) a division of a game during which one team is on the offensive
a time period for working (after which you will be relieved by someone else)

turn (verb)	change form (verb)
twist suddenly so as to sprain	assume a different shape or form
change to the contrary
go sour or spoil
pass into a condition gradually, take on a specific property or attribute; become
undergo a transformation or a change of position or action
change color
become officially one year older
have recourse to or make an appeal or request for help or information to
direct at someone
shape by rotating on a lathe or cutting device or a wheel
let (something) fall or spill from a container
alter the functioning or setting of
cause (an object) to assume a crooked or angular form
to break and turn over earth especially with a plow
to change orientation or direction
cause to move around a center so as to show another side of
cause to move around or rotate
pass to the other side of
move around an axis or a center
to send or let go
cause to move along an axis or into a new direction
channel one's attention, interest, thought, or attention toward or away from something
get by buying and selling
accomplish by rotating
undergo a change or development
cause to change or turn into something different;assume new characteristics