Change a template's message, or send channel_id to attach it to a campaign's text channel. Every call replaces content, and also landing_page_id and review_site_id (left out = cleared); name keeps its value when left out. Editing a shared (global) template saves a copy under your account with a new id (400 if your account already has a template with that name). Returns the updated template.

Prerequisites: a bearer token and the template's id (value in GET /api/v1/campaign/template/sms/list). Optional: a campaign channel id (channel_id, from data.data.channels[].id in the campaign create step 2 or 3 response).

Authentication: Account token. sms_template_id must be one of your account's templates or a shared template, and channel_id must be a channel of a campaign on a location inside your own account tree; otherwise 422.

Rate limit: none.