The Cercanías (Suburban), Rodalies (Commuter) and Metric Gauge services do not allow changes.
On AVE (high-speed), AVE International between Spain and France, Alvia, Euromed and Intercity trains, the terms and conditions for changes will depend on the option (Básico, Elige or Prémium) you have purchased:
You can upgrade your journey by purchasing, for an extra cost, unlimited free changes (allowing you to change the date and time of travel as often as you like without being charged for it, only paying the price difference with the new ticket, if any; only for departures and arrivals within Spain), Puente AVE (you can bring your departure forward or delay it on the same day as the journey, without change fees and without paying a price difference) and Superflex Pack (includes unlimited free changes, Puente AVE and full refund, only for departures and arrivals within Spain).
The origin and destination cannot be changed.
In Avant (mid-distance high-speed) and Media Distancia (mid-distance) trains, the change conditions will depend on the fare you have purchased:
Tickets may be changed up to a maximum of 3 times, within their validity period. The origin and destination cannot be changed.