I think you are misunderstanding this. The password is hashed. Hashing is a process where a string is converted into another string by a mathematical process (to keep it very simple).
Once a string has been hashed, it cannot be reversed to plain text under normal circumstances (this is intentional).
If you wish to check a password for authentication, for example, then the process is to hash the string you want to check and if it hashes to the same result, then strings are the same. You will need to factor in the salt used, as there is one in that hash.
The function password_hash() is simply a wrapper for crypt().
I suggest looking at http://php.net/password_hash, http://php.net/hash_equals and http://php.net/crypt for further information.