The Specialized Sirrus is a line of bicycles that has included such models as the LTD, Pro, Sport and Comp. All have flat bars and mountain bike components.
You can swap the flat handlebars for road-style drop bars, but it will take more than a simple trade. Components like the brake levers, shifters, brakes and derailleurs likely will need to be changed out as well.
It is possible to get the ergonomics of a road bike without swapping multiple components. One option is to add bar ends to your handlebars, which will give you the choice of an alternative hand position.
A second option is to purchase a longer stem. A longer stem will make you lean forward, similar to being on a road bike.
A final option is installing aero bars, which put you in a forward, aerodynamic position, according to Bicycling Magazine.
Any repair that involves the steering system of your bicycle can be hazardous to your life and health if performed incorrectly. If you have doubts about your ability to perform these repairs, take your bike to a qualified mechanic.