# switch

URL: /business/nouns/subscription/switch · Id: `verb:Subscription.switch` · Call: `await $.Subscription.switch({ … })` (SDK) or the `do` tool at `https://api.sb/mcp`. Inputs says what to pass, Outputs what returns, When it waits who approves.

> Switch moves a Subscription to another Offer and prorates the current period.

Switch moves a [Subscription](/business/nouns/subscription) to another [Offer](/business/nouns/offer) and prorates the current period.

## Inputs
| Input | Type | Required | Description |
| --- | --- | --- | --- |
| `subscription` | [Subscription](/business/nouns/subscription) | Yes | The Subscription to move. |
| `offer` | [Offer](/business/nouns/offer) | Yes | The Offer to move to. |
| `effectiveAt` | `datetime` | No | When the move takes effect; moving existing Customers to a higher Price waits at least the notice period. |

## Outputs
| Output | Type | Required | Description |
| --- | --- | --- | --- |
| `subscription` | [Subscription](/business/nouns/subscription) | Yes | The Subscription on its new Offer. |

## Effects
- Emits [`Subscription.switched`](/business/events/Subscription.switched).
- Performed by the [Billing Specialist](/agents/finance/billing-specialist).
- Two-way: it runs at once, in the `try`, `send` and `do` modes.
- Bills or credits the prorated difference at once.
- Moving existing Customers to a higher Price sends notice and switches each at its first renewal after the notice period.
- A move to a cheaper Offer runs at once, with no Limit, Approval or delay window.

## Refuses when
| Check | Error | Fix | Then call |
| --- | --- | --- | --- |
| The input does not match the schema of the operation. | [`invalid-input`](/code/api/errors/invalid-input) | Read the schema of the operation, then send every required field with the right type. | [Subscription.switch](/business/nouns/subscription/switch) |
| The operation is part of an Offer the caller has not accepted or paid for. | [`payment-required`](/code/api/errors/payment-required) | Accept the Offer named in the response, then retry the call. | [Offer.accept](/business/nouns/offer/accept) |
| The key is valid, but its scopes do not allow this operation. | [`forbidden`](/code/api/errors/forbidden) | Use a key whose scopes cover the operation, or ask an owner of the namespace to grant them. | [Subscription.switch](/business/nouns/subscription/switch) |
| The record is not in a state that allows this Verb, so the call is refused. | [`refused`](/code/api/errors/refused) | Read the record, run the Verb that moves it to an allowed state, then retry. | [Subscription.switch](/business/nouns/subscription/switch) |

## When it waits
| Gate | Default |
| --- | --- |
| Decision class | Low: two-way, nothing at stake |
| [Delay window](/systems/trust-and-governance/controls/one-way-windows) | None: it runs once review passes. |
| Limit | The call [Limit](/business/nouns/limit) of the [Permission](/business/nouns/permission) it runs under. |
| Over the Limit | It waits `pending` for an [Approval](/business/nouns/approval) from the [Founder](/agents/founding/founder). Approved, it runs; refused, it ends `refused` with [`limit-exceeded`](/code/api/errors/limit-exceeded); unanswered by its deadline, it ends `canceled`. |

## Example

**Ask**

```text
Switch the latest subscription with an offer.
```

**API**

```bash
curl -X POST https://api.sb/shiftnote.app/subscriptions/subscription_1/switch \
  -H "Authorization: Bearer $STARTUP_BUILDER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"offer":"offer_1"}'
```

```json
{
  "api": "https://api.sb/shiftnote.app",
  "subscription": {
    "$id": "https://api.sb/shiftnote.app/subscriptions/subscription_1",
    "$type": "Subscription",
    "status": "active"
  },
  "action": {
    "$id": "https://api.sb/shiftnote.app/actions/action_1",
    "operation": "Subscription.switch",
    "status": "done"
  },
  "links": {
    "self": "https://api.sb/shiftnote.app/actions/action_1"
  }
}
```

**SDK**

```ts
import { $ } from 'startup-builder'

const subscription = await $.Subscription.switch({ subscription: 'subscription_1', offer: 'offer_1' })
```

**CLI**

```bash
npx startup-builder do Subscription.switch --json '{"subscription":"subscription_1","offer":"offer_1"}'
```

**MCP**

```json
{
  "name": "do",
  "arguments": {
    "code": "return await $.Subscription.switch({ subscription: 'subscription_1', offer: 'offer_1' })"
  }
}
```