If someone doesn't remember their Keychain password or they're having an issue where they are getting constant pop-ups asking for their keychain password, you can Delete and Reset their keychain.
 

1. While on the Desktop, hold down the Option (Alt) Key, and then go to the top toolbar and click on Go >  Library.
   
    
2. Inside the Library Folder, open the folder called Keychains .
   
    
3. Inside Keychains  there will be a folder whose name is a string of random numbers and letters. Move this Folder to Trash, and then Restart the computer.
   
    
4. When you go to Login after restarting, there will be a pop-up window asking about Keychain. Click on "Create New Keychain".