# Simulate Reversals

A reversal is a request to reverse or undo the effect of an authorization.

## Create a Simulated Reversal

A simulated reversal is created by calling the simulate reversal API and supplying the identifier of the authorization and the amount to reverse.

The `authorizationId` is the identifier of an authorization that was created by calling the [Create a Simulated Authorization](https://docs.sudoplatform.com/guides/manage-authorizations#create-a-simulated-authorization) API. The `amount` supplied as input is expressed as a multiple of the smallest unit of currency the merchant accepts. For example if the currency is US dollar then the amount is the number of US cents.

An example implementation of creating a simulated reversal is:

{% tabs %}
{% tab title="TypeScript" %}

```typescript
try {
  const result = await simulatorClient.simulateReversal({
    authorizationId: authorization.id,
    amount: 4200,
  })
} catch (error) {
  // Handle error
}
```

{% endtab %}

{% tab title="Swift" %}

```swift
do {
    let reversalInput = SimulateReversalInput(
        amount: 4200,
        authorizationId: authorization.id
    )
    let response = try await simulatorClient.simulateReversalWithInput(
        reversalInput
    )
    // Reversal has been applied
} catch let error {
    // Handle/notify the user of error
}
```

{% endtab %}

{% tab title="Kotlin" %}

```kotlin
val reversalInput = SimulateReversalInput(
    authorizationId = authorization.id,
    amount = 4200
)
launch {
    try {
        val reversal = withContext(Dispatchers.IO) {
            simulatorClient.simulateReversal(reversalInput)
        }
        // Reversal has been applied
    } catch (e: ReversalException) {
        // Handle/notify the user of exception
    }
}
```

{% endtab %}
{% endtabs %}

This API call reverses the effect of the authorization against a virtual card. If an exception occurs, the error or exception will contain a description of the fault that caused the exception.