Is there a way reset the password without logging into the RPI first?
ssh is the abbreviation for Secure SHell. It would break any meaning of this name if you are able to modify/reset the password without authentication. You can't never do it remotely (except you are using an unknown exploit). You have to login local with keyboard and monitor attached provided you know the password of another account (root) that can modify passwords of other user. Otherwise you have to put out the SD Card of the RasPi and attach it with your card reader to a computer that is able to read the ext4 file system. MS Windows can't. Then you have to modify
etc/shadow on the SD Card. For example, if the second partition (ext4 formated root partition) of the SD Card is mounted to
/mnt/, you can reset the root password:
/mnt/etc/passwd set line
/mnt/etc/shadow set line
root:::: (4 colons are important!)
If you boot the SD Card next in the RasPi then login with user root and just hit enter when asked for the password. Don't forget to set immediately a new password.