Available parameters and response documentation is available here

GET /lookup/lifted-over-variant/15-73027478-T-C
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Cache-Control: max-age=900
Content-Type: application/json ;utf-8
ETag: "0623417061cc2d16c7fa5d3ef0faaeb4e141e0524c7a69168b6a5de065c9a7df"
Vary: Accept

[
  "chr15-72735137-T-C"
]