Ok, have some questions, and some info..
1) try /usr/bin/chpasswd    very powerful tool for automation
via stdin  you give it userid:password (list of many if you want to change 50 id's at once (1 id per record)
-c flag  (removes admchg flag in /etc/security/passwd
-e flag says the password you're providing is already encrypted (good if you want to override pwd_alg in /etc/security/loign.cfg

QUesiton to you.. what do you mean "reset"??
as in set it "back" to seomthing? that implies you have a list of what that previous "something" was which can be a security risk in itself.
If you just want to reset failed login attemts.. .use chuser

guess I'm not clear on what you're trying to accomplish... can you give an example of how this would be used..