##in console write: pip uninstall <packagename>
pip uninstall <packagename>
#the best way to install pip if uninstalled is using the following command
python -m ensurepip
# not only it will check whether there is pip installed , it will install
# for you if not found
To install it again : python -m pip install --upgrade pip
This is in windows command prompt or powershell
python -m ensurepip --upgrade