Update external feed
Updates configuration of an existing external feed.
**Use this to:**
- Update feed URLs when data sources change
- Modify authentication credentials
- Change cache and retry settings
- Update custom headers
- Rename feeds for better organization
**Key information returned:**
- Success confirmation message
**Important considerations:**
- Only provided fields will be updated
- Feed UUID must exist in your account
- Authentication changes require verification
- URL changes should be tested before campaign use
- Monitor campaigns using this feed after updates