Change one Letter

Son = Sun................

sun = gun.........

gun=nut...

nut = but............

but=tut...

Tut =Tit.............

tit = wit...............

wit=tin...

Tin = Ink..............

ink = inn.................

inn=ion....

Ion = Nil..............

nil = ill..............

Ill = Lit................

lit = let...........