washing machine problem?

Actually my washing machine is leaking from front door.when i chacked it i saw the rubber seal lip was cutted bcoz of that the it was leaking.can i mend it without changing sealing? it if yes. how? if no then please tell me how can i change the rubber seal or gasket. can somebody plz tell me how to change the sael. do i have to remove the front cover or just to remove the door.