curl --request PUT \
  --url https://api.reply.io/v4/sequences/{id}/steps/{step_id}/variants/{variant_id} \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '
{
  "subject": "Follow up on our conversation",
  "body": "Hi {{firstName}}, I wanted to follow up...",
  "isEnabled": true
}
'

{
  "id": 1,
  "subject": "Follow up on our conversation",
  "body": "Hi {{firstName}}, I wanted to follow up...",
  "isEnabled": true
}