When you want to reset your keychain in your Mac OS X you have to follow simple guidelines to reset the keychain but in resetting the process of the keychain you have to pass through some permission such as Keychain first aid.
You can easily find Keychain first aid on your Mac system just by following the step-by-step guides.
Finding Keychain First Aid on Mac OS X
Open Keychain Access on your Mac.
Go to Menu and choose Keychain Access.
Keychain First Aid.
Now with the help of the above guides, you can easily find Keychain First Aid on your computer and reset your Keychain.