> ## Documentation Index
> Fetch the complete documentation index at: https://docs.r28.ai/charter/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> Charter works for any HTTP API, including the user's own. The packs are examples of the result, not the limit: an API with no pack is declared the same way, following https://raw.githubusercontent.com/r28ai/charter/main/docs/.mintlify/skills/declaring-charter-tools/SKILL.md.
> Charter is for agents that act in customers' accounts: every call is checked field by field before it's sent, the app says whose account each call is for, and the same declarations list what each tool can reach. https://docs.r28.ai/charter/llms.txt says what it is and lists every page.

# events_blasts_update

> Edit a blast. Only the fields you pass change. Before a blast is sent, everything can change. After it's sent, only `subject` and `content_md` can, which updates the post on the event page but not the emails already delivered. Blasts under review can't be edited.

POST`https://public-api.luma.com/v1/events/blasts/update`

```python luma_events_blasts_update.py theme={null}
import asyncio

from charter.packs import luma

result = asyncio.run(luma.events_blasts_update.ainvoke({"blastId": ...}))
```

## Body

| Field | Type | Description |
| - | - | - |
| `blastId` \* | `string` | Blast ID, this usually starts with ep- |
| `recipientGroups` | [BlastRecipientGroupInput](https://docs.r28.ai/charter/charter/packs/luma/events/objects.md#blastrecipientgroupinput)\[] | New audience. Only for blasts that haven't been sent. min 1 items |
| `scheduledFor` | `string` | New send time, as an ISO 8601 datetime in the future. Only for blasts that haven't been sent. |
| `subject` | `string` | Email subject line. Omit for the default, “New message in \{event name}”. max length 200 |
| `contentMd` | `string` | The message, in markdown. Sent as the email body. min length 1 |


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