How to i access my wireless router network and change the pword (I dont know the current pword)?

I just moved into my apartment and it came with cable modem and wireless router all set up. a wireless network is already set up and the name is my apartment number. I cant access it becuase i dont know the pword. Is there a way i can reset the router and make my own network? or connect to the current one set up and change the pword? It is a Cisco Linksys wireless router. model #WRT54G2V1