Cannot figure out how to factory reset C3000 router

This is a wireless n300 router with model number c3000 running on Windows 10. Somehow i've managed to mangle the admin password for router login (note: NOT the wifi password--i'm up and running with no problem but i can't make any changes to router settings).  All the documentation however directs me to login to the router (!) to do anything I would normally do like change the password or do a factory reset.  Some other models i notice have a handy reset button on the back, howeever this model does not.  Any recommendation on how to get past this, or how to do a reset without having to login to router?