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# Importing Transactions from other Billing Systems to Subscribe

Use `Transaction.migrate` to migrate historic Transaction information into Subscribe. Each `MigrationTransaction` included in the `migrate` call will result in the creation of a `Transaction` that can be operated on (`fetch`, `refund`, and etc.) as if it had originated in Subscribe. Note, however, that some operations (`refund`) require that the `Transaction` be in one of the following states:

* `Captured`
* `Refunded`
* `Settled`

After you send data to Subscribe, Subscribe will issue a Return object with `returnCode` and `returnString` to inform you if the call completed successfully. (Codes for the `Return` object are modeled after standard HTTP return codes). If the call succeeds, you receive a code of 200 and the string OK. `returnCode` and `returnString` may be used to interpret errors. If one or more of the `MigrationTransactions` included in the `migrate` call failed to be migrated, the return will also include an array of `TransactionValidationResponse` objects describing how/why the migration attempt failed. Be certain to act upon the `TransactionValidationResponses` returned.

For more information, see Transaction.migrate in the ***Subscribe API Guide***.

**Parent topic:**[Working with One-Time Transactions](../topics/ProgGuide_Transactions)


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