How do I change the Assignee using CURL - Jira Rest API

Question

How do I change the Assignee using CURL - Jira Rest API?

I tried the following:
@jqlassignuser.json -H "Content-Type: application/json" https://p97networks.atlassian.net/rest/api/2/issue/ACB-65/assignee > results.tx

where jqlassignuser.json contains the following:
{
   "fields": {
      "assignee": {
         "name": "charles.teague"
      }
   }
}

Here are the results:
{"errorMessages":["Unrecognized field "fields" (Class com.atlassian.jira.rest.v2.issue.UserBean), not marked as ignorable
 at [Source: org.apache.catalina.connector.CoyoteInputStream@11835c39; line: 1, column: 14] (through reference chain: com.atlassian.jira.rest.v2.issue.UserBean["fields"])"]}

Charles Teague · Accepted Answer

Changing the the json file to the following worked:

{"accountId": "557058:d166e0cb-9558-43a2-99ff-36636f97f02a"}

I got the accountId by writing a .Net project in c# and used Atlassian.Net to query for an issue assigned to "charles.teague".  The accountId is in the issue.AssigneeUser.AccountId property, which was set when calling the following:

Jira jira = Jira.CreateRestClient(jiraData.Url, jiraData.UserName, jiraData.PasswordToken);
Issue issue = await jira.Issues.GetIssueAsync(issueKey);

with the following set:

* string Url { get; set; } = @"https://[companyJiraUrl].atlassian.net";
* string UserName { get; set; } = @[jira email address];
* string PasswordToken { get; set; } = @[Token you generated -- see https://confluence.atlassian.com/cloud/api-tokens-938839638.html";
* issueKey is to the issue assigned to "charles.teague".
* jira is from the Atlassian.Net NuGet package.

Note: You can delete the token when you are finished.