If the user can log in then he or she can change the password from directly from the Account Info page or else the user needs to contact Yahoo technical support and follow the instructions for Yahoo account recovery system to do the needful.

To recover Yahoo password without being able to log into the account, the user first need to

Ø Open the Yahoo homepage and Visit yahoo.com in the browser. If the internet service provider (ISP) uses Yahoo as their account such as AT&T, BT, Sky, Frontier, Verizon, Spark, Rogers or MTS then he or she just need to contact their customer service department and follow their instructions on changing the account password.

Ø Then Click the "Sign In" button which will unfold a page showing that the user is not currently logged into the Yahoo account

Ø Then he or she Log in with the Yahoo account. If the user is not aware of his or her own Yahoo password then he or she needs to check the Resetting a Forgotten Password section for the same

Ø After that the user need to click the profile name in the upper-right corner which replaces the "Sign In" button after the user logged in

Ø Then select "Account Info" which directly beneath the Yahoo email account in the window that appears

Ø Click "Account security"

Ø And after that click "Change password" which will be prompted to answer the security questions

Ø After that the user needs to create a new password and reenter it to confirm. The new password will take effect immediately and the user will be signed out of the connected devices

Ø The again he or she needs to sign in with their new password on all of the devices

Source by :- http://www.ysupportnumber.com/