All ICANN accredited registrars and their domain name resellers follow what is called a “Uniform Dispute Resolution Policy” (UDRP).
Under that policy, disputes over ownership of a domain name are usually resolved by court action (litigation) between the claimants.
Once the Court rules as to who is entitled to the registration, the domain name registrar will follow that ruling and, if necessary, will transfer the domain name to the owner designated by the Court.
In disputes arising out of abusive registrations, e.g. “cyber squatting” and “cyber piracy”, the UDRP provides a fast-track procedure allowing the dispute to be resolved without the frequent cost and delays of Court litigation.
In those cases, you can apply to one of the domain name dispute resolution service providers.