Can You Amend Your Claims After Filing a Lawsuit?

Short Answer

Generally, yes. In Korean civil litigation, a plaintiff may amend the relief sought or the cause of action after filing a lawsuit, but only within certain procedural limits.

In general, the amendment must be made before the close of oral argument, must not change the basis of the claim, and must not materially delay the proceedings.

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When Might a Claim Need to Be Amended?

A claim may need to be amended for several practical reasons.

For example, a plaintiff may need to:

• Increase or reduce the claim amount
• Correct the legal basis of the claim
• Add more detailed factual allegations
• Modify the requested relief
• Reflect newly discovered evidence
• Adjust the claim after reviewing the defendant’s response

In commercial disputes, this often happens when the plaintiff initially files the case based on limited information and later obtains additional documents during the proceedings.

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Can You Increase the Claim Amount?

Yes, in many cases.

If the plaintiff later confirms that the actual damages or unpaid amount are higher than initially claimed, the plaintiff may seek to amend the claim amount.

However, increasing the claim may affect court fees, litigation strategy, and the scope of the defendant’s response. In Korea, additional court stamp duty may be required depending on the increased claim amount.

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Can You Change the Legal Argument?

Yes. A party may refine or adjust its legal arguments during the litigation.

For example, a plaintiff may initially frame the case as a breach of contract claim but later also rely on unjust enrichment, tort, or another legal basis, depending on the facts.

That said, the amendment should remain connected to the same core factual basis of the dispute.

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Can You Add a New Claim?

Sometimes.

A new claim may be added if it arises from the same underlying transaction, core facts, or economic interest in dispute.

However, if the proposed new claim is based on a substantially different factual or legal relationship, the court may refuse the amendment. In that case, the claim may need to be brought as a separate lawsuit.

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Can You Amend Claims on Appeal?

In principle, yes.

Because the appellate court is still a fact-finding court in Korea, claim amendments may be permitted at the appellate stage if the statutory requirements are satisfied.

However, the later the amendment is made, the more carefully the court may examine whether it changes the basis of the claim or materially delays the proceedings.

At the Supreme Court stage, claim amendments are generally much more limited because the Supreme Court mainly reviews legal issues.

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Are There Risks in Amending Claims?

Yes. Although claim amendments are often permitted, they can create practical risks.

Possible issues include:

• Additional court fees
• Delay in the proceedings
• Additional response time for the defendant
• Greater evidentiary burden
• Risk that the court may refuse the amendment
• Strategic exposure if the amendment appears inconsistent with earlier arguments

For this reason, amendments should be made only after reviewing both the legal basis and the procedural impact.

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When Is the Best Time to Amend a Claim?

As a practical matter, amendments should be made as early as reasonably possible.

The later the amendment is made, the more likely it is to raise procedural objections or delay concerns. Early amendment also helps the court and the opposing party understand the actual scope of the dispute.

If new evidence, new calculations, or new legal grounds become available during the case, the party should promptly consider whether an amendment is necessary.

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Key Takeaways

• A plaintiff may generally amend claims after filing a lawsuit in Korea.
• The amendment must generally be made before the close of oral argument.
• The amendment must not change the basis of the claim.
• The amendment must not materially delay the proceedings.
• Increasing the claim amount may require additional court stamp duty.
• A new claim should usually arise from the same core facts or economic interest.
• Claim amendments should be made early and strategically.

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Conclusion

Amending claims is a common and important part of Korean civil litigation.

A lawsuit does not always remain fixed exactly as originally filed. However, any amendment should be carefully prepared to ensure that it is procedurally permissible, supported by evidence, and consistent with the overall direction of the case.

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