When updating pip, the error goes out and it does not let you update it

Using the get-pip.py of link , I execute the following commands:

python -m pip install --upgrade pip

python -m pip install -U pip

In both cases, I always get this error and it never lets me update it.

Collecting pip
  Using cached pip-9.0.3-py2.py3-none-any.whl
Installing collected packages: pip
  Found existing installation: pip 9.0.1
    Uninstalling pip-9.0.1:
Exception:
Traceback (most recent call last):
  File "C:\Program Files (x86)\Python36-32\lib\shutil.py", line 544, in move         os.rename(src, real_dst)
PermissionError: [WinError 5] Acceso denegado: 'c:\program files(x86)\python36-32\lib\site-packages\pip-9.0.1.dist-info\description.rst' -> 'C:\Users\aula3\AppData\Local\Temp\pip-5dvshf3s-uninstall\program files (x86)\python36-32\lib\site-packages\pip-9.0.1.dist-info\description.rst'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Program Files (x86)\Python36-32\lib\sitepackages\pip\basecommand.py", line 215, in main status = self.run(options, args)
  File "C:\Program Files (x86)\Python36-32\lib\sitepackages\pip\commands\install.py", line 342, in runprefix=options.prefix_path,
  File "C:\Program Files (x86)\Python36-32\lib\site-ackages\pip\req\req_set.py", line 778, in install requirement.uninstall(auto_confirm=True)
  File "C:\Program Files (x86)\Python36-32\lib\sitepackages\pip\req\req_install.py", line 754, in uninstall paths_to_remove.remove(auto_confirm)
  File "C:\Program Files (x86)\Python36-32\lib\sitepackages\pip\req\req_uninstall.py", line 115, in remove renames(path, new_path)
  File "C:\Program Files (x86)\Python3632\lib\sitepackages\pip\utils\__init__.py", line 267, in renames shutil.move(old, new)
  File "C:\Program Files (x86)\Python36-32\lib\shutil.py", line 559, in move os.unlink(src)
PermissionError: [WinError 5] Acceso denegado: 'c:\program files(x86)\python36-32\lib\site-packages\pip-9.0.1.dist-info\description.rst'
You are using pip version 9.0.1, however version 9.0.3 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.