And hit dd command to delete line. Save and close the file. Or use following
vi ~/.ssh/known_hosts
OR
vi /var/root/.ssh/known_hosts
Now go to line # 2, type the following command
:2
Now delete line with dd and exit:
dd
:wq
https://www.cyberciti.biz/faq/warning-remote-host-identification-has-changed-error-and-solution/