If you want to modify, let’s say, the parameter ask_limit_on_launch to True, you should do this by patching through an API call:
curl -X PATCH -H "Content-Type: application/json" --user <USER>:<PASSWORD> -k https://<AWX_URL>/api/v2/job_templates/<JOB_ID>/ -d '{"ask_limit_on_launch": "true"}' | jq .
After doing that you can pass limit as a content when executing a job:
curl -X POST -H "Content-Type: application/json" --user <USER>:<PASSWORD> -k https://<AWX_URL>/api/v2/job_templates/<JOB_ID>/launch/ -d '{"limit": "<HOST1>,<HOST2>"}' | jq .
You’re all set.