change, alter, morph, transpose...
alter
It is called a "letter manipulation" or a "word transformation."
Anagram
It's called an anagram.
A word that forms a different word when read backwards is called a palindrome. Examples include "radar," "level," and "madam."
A prefix is the letters used to make a different word or sound on a root or base word such as fixed, with a prefix it can become unfixed meaning not fixed or broken
a homophone
A word with the same pronunciation as another but with a different meaning is called a homophone.
No, but if it is widely used it make become a 'real word'.
To make or become better
It is called a cepitriney.
Anadrome