When your employer can change your role, schedule or pay (modificación sustancial)

Key rules

• Notice: Your employer must give you written notice before the change starts, not after.
• Reason: The employer must prove a genuine business reason, and a court can review it.
• Your choice: You can accept, challenge in the labour court, or leave with compensation if the change harms you.
• Compensation: Leaving compensation is capped and applies only to certain kinds of change, not to every change.

The short answer

Your employer cannot change your core working conditions whenever it likes. A substantial change (a modificación sustancial) needs a real business reason and written notice. You then choose: accept it, challenge it, or, in some cases, leave with compensation.

Which changes count

The rules cover major changes to:

• working hours
• your work schedule
• your shift system
• your pay system
• your work-performance system
• your duties, when they go beyond your job category

Other, smaller changes fall under the employer's ordinary power to manage the business, and these rules do not apply to them. Terms set by a sector-wide collective agreement (convenio colectivo estatutario) cannot be changed this way. Employers have a separate, stricter route for those.

The employer needs a real reason

The employer must prove economic, technical, organisational or production reasons. These are reasons linked to the company's competitiveness, productivity or organisation of work. The change must be reasonable and connected to that reason. If you challenge it, the labour court checks the proof.

Notice you must receive

Your employer must give you written notice at least 15 days before a substantial change takes effect. The employer must also tell your workers' representatives, if you have any.

Individual or collective change

A change is collective if, within 90 days, it affects at least:

• 10 workers, in a company with fewer than 100 staff
• 10% of the workforce, in a company with 100 to 300 staff
• 30 workers, in a company with more than 300 staff

In a collective change, your employer must first consult your workers' representatives for up to 15 days. If there are none, a committee of union or elected representatives takes their place. The aim is to reach agreement and to avoid or soften the effects. The employer announces its decision after that period ends. The notice period above still applies. Your collective agreement may add further steps, so check it.

Your options

Accept. If you accept, or do nothing, the change takes effect.

Challenge it in the labour court. If the court finds the change unjustified, you go back to your previous conditions. Take advice quickly, because challenges have short deadlines. A union or a labour lawyer can tell you the exact one for your case.

Leave with compensation. If the change harms you, you can end your contract and receive 20 days' salary per year of service, up to 9 months. This right applies to substantial changes to working hours, shift schedule, work system, pay system or performance level. It does not apply to every change. Even if you challenge the change, you can still ask to end your contract on the grounds that it harms your dignity.

The decision and timeline below set these choices out step by step. The "What if I refuse" section covers what happens if you say no.

Choosing between options

What do you do when your employer imposes a substantial change?

• Accept the change: The change is reasonable for you and you are happy to work under the new terms.

• Challenge it in the labour court: You think the cause is not real or the change is not justified. If the court agrees, you go back to your former conditions. You have 20 working days from notification.

• End your contract with compensation: The change affects your working day, shift schedule, work system, pay system or performance level and harms your training or dignity.

Challenge the change if you want your old terms back. Leave with compensation only if the change is one of the listed types and harms your training or dignity. If the change is collective, your representatives have already been consulted, but your own options stay the same.

Timeline and deadlines

• If the change is collective, your employer consults your workers' representatives and seeks agreement: for up to 15 days before the decision

• You accept the change, or challenge it in the labour court: within 20 working days of being notified

What if I refuse the change my employer announced?

Don't just refuse. Refusing outright can get you fired for disobedience, and a later court win may not undo that.

Why refusing is risky

Once the notice period ends, the change applies right away, even if you challenge it in court. The notice is 15 days for a change to your working conditions and 30 days for a relocation. Challenging the change does not pause it.

Courts generally treat a refusal to follow the change as disobedience, which can justify disciplinary dismissal. This holds even if the change is later found to be unjustified. Your remedy is to comply and challenge, not to refuse. Courts have sometimes let a refusal pass when the change was clearly unlawful or abusive, or when it harmed your dignity. You carry the risk if the court disagrees. Get legal advice before refusing.

The safer course: comply and challenge

Do the new work or go to the new place, and challenge the change in the labour court within 20 working days of being notified. If the court finds the change unjustified, it orders your previous conditions restored.

Before filing, you must first attempt conciliation or mediation, which pauses the deadline. Check what exact step applies now with the labour court or your regional conciliation service.

Will working under the new terms mean you accepted?

Not if you file within the deadline. Working under the new terms does not remove your right to challenge. After the deadline, though, the change becomes final. A long stretch of working under the new terms with no protest and no claim can also be treated as acceptance. Don't wait.

The exit if you don't want to stay

If the change is a relocation, you can end your contract instead of accepting it. You must give notice within the same 20 working days.

If the change affects many employees

Employee representatives can challenge it as a collective dispute. Individual claims are then put on hold while that case is pending.

Frequently asked questions

Can my employer change anything in my contract this way?

No, terms set by a collective agreement signed under the Workers' Statute cannot be changed through this procedure. For those terms, the employer needs a separate route called an opt-out (descuelgue). The procedure covers working hours, schedule, shift system, pay system, work-performance system and duties beyond your job category.

When does a change count as collective instead of individual?

A change is collective when, within 90 days, it affects at least 10 workers in a company with fewer than 100 staff, 10% of the workforce in a company with 100 to 300 staff, or 30 workers in a company with more than 300. Your employer must then consult your workers' representatives for up to 15 days before deciding.