curl --request DELETE \
  --url https://realtime-api.voiceflow.com/v1/stable/function-variable/<variableID> \
  --header 'Authorization: Bearer <token>'

const response = await fetch('https://realtime-api.voiceflow.com/v1/stable/function-variable/<variableID>?projectID=<projectID>&environmentAlias=<environmentAlias>', {
  method: 'DELETE',
  headers: {
    Authorization: 'Bearer <token>',
  },
});
const data = await response.json();

import requests

response = requests.delete(
    'https://realtime-api.voiceflow.com/v1/stable/function-variable/<variableID>?projectID=<projectID>&environmentAlias=<environmentAlias>',
    headers={'Authorization': 'Bearer <token>'},
)
data = response.json()

vf function variable delete --variable-id <variableID> --project-id <projectID> --environment-alias <environmentAlias>