Use of Override in Ansible Provisioner

My original need/question is below, but could not find any documentation to support or dissuade me from attempting it. Ive pasted a small snippet below, it does not work, and can’t find a reason through. Any breadcrumbs would be helpful and very appreciated, thank you.

Q: Can you use the override option under the Ansible provisioner to change the builder’s ssh user and password mid-build? And what would that look like?

Code Snippet:

“type”: “ansible”,
“playbook_file”: “playbook_foo.yml”,
“user”: “{{user service_name}}”,
“extra_arguments”: [
“service_name={{user service_name}}”,
“ansible_ssh_pass={{user service_pw}}”,
“ansible_become_pass={{user service_pw}}”,
“override”: {
“amazon-ebs”: {“ssh_username”: “{{user service_name}}”}