Declining a relocation is usually permitted and rarely free. What matters is whether the role itself is moving: if it is, declining can become a redundancy, a redeployment, or in some framings a resignation, and those three have very different consequences for notice and severance. Establish which applies, in writing, before you give an answer.
The question that decides everything
Is the role moving, or is this an opportunity? An opportunity can be declined with little more than a conversation. A role that is relocating and being declined has to be resolved somehow, and how it is characterised determines what you are entitled to.
The three characterisations
Redeployment. The employer finds you something else. Best outcome and worth asking for explicitly rather than waiting to be offered it.
Redundancy or layoff. Your position no longer exists where you are. This can carry notice and severance depending on policy, contract and jurisdiction.
Resignation. Treated as you choosing to leave. Usually the worst outcome, and sometimes the default framing if nobody establishes otherwise.
The same facts can be presented as any of the three, which is exactly why the framing should be settled while it is still a discussion.
What to ask, and to get in writing
Is the role relocating or is this optional. If I decline, is redeployment considered, and over what period. How would my departure be characterised. Is there a mobility clause in my contract, and what does it actually say.
Mobility clauses
Many contracts contain one, and many are broader than they look. Whether it is enforceable in practice depends on the jurisdiction, how reasonable the requirement is and how it is exercised — which is a matter for an employment lawyer rather than a guess, particularly where severance is at stake.
Declining well
Give the answer early rather than late, state a reason that is about circumstances rather than the role, and ask about redeployment in the same conversation. An early no with a constructive question attached is treated very differently from a late one.
Common questions
Can I refuse a relocation?
Usually yes. What matters is whether the role itself is moving, because that decides how your departure or redeployment is handled.
Could declining count as resigning?
It can be characterised that way, which is usually the worst outcome. Establish the framing in writing before you answer.
Might I get severance?
Possibly, if the position no longer exists where you are and it is treated as a redundancy. That depends on policy, contract and jurisdiction.
What is a mobility clause?
A contract term allowing the employer to change your work location. Many are broader than they look, and enforceability is a question for an employment lawyer.
How should I decline?
Early, with a reason about circumstances rather than the role, and with an explicit question about redeployment in the same conversation.