Resetting cisco 2610 as Username and Password

[tselvan]

Dear friends,   In one of my client place a new administrator has taken over the incharge of network. They are using cisco 2610 router for which the admin doesnot know the username and password for cisco 2610 router. Recently they want to configure a leased line to internet in cisco 2610 router .   They have contacted me to Reset the router   Help me in this regard.   Regards Selvan