#includedir /etc/sudoers.d
web ALL=NOPASSWD: ALL
somebody ALL=NOPASSWD: ALL

web@web01:~$ sudo -u somebody sudo echo "success"
[sudo] password for web:

web@web01:~$ sudo su - somebody
Last login: Wed Mar  1 01:22:27 CST 2017 on pts/1
somebody@web01:~$ sudo whoami
root
somebody@web01:~$ exit
web@web01:~$ #success