If you need to delete an application but are unable to do so because it is “locked”, right click the application within the “applications” folder and select “Get Info” from the menu.  From here you should be able to “unlock” the application.

If you are unable to “unlock” because the option is greyed out, open a terminal window and type the following:

cd “/applications”
sudo chflags noschg “<application_name>.app”