Since 2010 it is no longer possible to change the contact information of the domain holder trough a registrar. The domain holder has to login at the registry with his NIC handle (can be found in WHOIS information...148389B-ESNIC-F5 in this specific case).
The password can be recovered here:
https://www.nic.es/sgnd/contacto/passRecoverInicializar.action?tContacto.nic.
The domain holder will then receive an email with his credentials. The email address of the domain holder and admin contact can only be changed only at the registry directly.