"Made himself of no reputation" is a common translation, but there are other translations. But what does that mean? He relinquished His glory, authority, power as God and became a man. He was in the "form of God" ( vs. 6)4 and made himself into the form of man. Many translations say emptied himself as if pouring himself out from heaven into a human vessel. Read some other translations:
ASV
but emptied himself, taking the form of a servant, being made in the likeness of men;
AMP
but emptied Himself [without renouncing or diminishing His deity, but only temporarily giving up the outward expression of divine equality and His rightful dignity] by assuming the form of a bond-servant, and being made in the likeness of men [He became completely human but was without sin, being fully God and fully man].
ESV
but emptied himself, by taking the form of a servant, being born in the likeness of a man.
HCSB
Instead He emptied Himself by assuming the form of a slave, taking on the likeness of men. And when He had come as a man in His external form,
PHILLIPS
Let Christ himself be your example as to what your attitude should be. For he, who had always been God by nature, did not cling to his prerogatives as God’s equal, but stripped himself of all privilege by consenting to be a slave by nature and being born as mortal man. And, having become man, he humbled himself by living a life of utter obedience, even to the extent of dying, and the death he died was the death of a common criminal. That is why God has now lifted him so high, and has given him the name beyond all names, so that at the name of Jesus “every knee shall bow”, whether in Heaven or earth or under the earth. And that is why, in the end, “every tongue shall confess” that Jesus Christ” is the Lord, to the glory of God the Father.
KJV
But made himself of no reputation, and took upon him the form of a servant, and was made in the likeness of men:
NASB
but emptied Himself
by taking the form of a bond-servant
and being born in the likeness of men.
TLB
but laid aside his mighty power and glory, taking the disguise of a slave and becoming like men.
NIV
rather, he made himself nothing by taking the very nature of a servant, being made in human likeness.
NKJV
but made Himself of no reputation, taking the form of a bondservant,
and coming in the likeness of men.
RSV
but emptied himself, taking the form of a servant, being born in the likeness of men.
VOICE
But He poured Himself out
to fill a vessel brand new; a servant in form and a man indeed. The very likeness of humanity,
WEB
but emptied himself, taking the form of a servant, being made in the likeness of men.
YLT
but did empty himself, the form of a servant having taken, in the likeness of men having been made,