Question: how do you change your facebook password if you forgot your old one?
Answer: Open Facebook: ... 
Tap Forget Password: ... 
Enter Your Email Address Or Phone Number: ... 
Tap Find Your Account: ... 
Select A Recovery Method: ... 
Send code via email: Facebook will send a reset code to the email associated with your Facebook account.
Tap Continue For Next Options: ... 
Retrieve your Facebook Account: