Check this out: https://communities.cisco.com/docs/DOC-49935
You would need to implement scheduling permissions. Scheduling permission essentially allows an account (generally one with Site Admin privileges) to schedule meetings on behalf of another user. Before this can be done, the “master account” being used must be added to each host account’s scheduling permission.
With the XML API, this can be done with a request like:
<serv:message xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:serv="http://www.webex.com/schemas/2002/06/service">
<header>
<securityContext>
<webExID>jdoe</webExID>
<password>letmein123</password>
<partnerID>123abc</partnerID>
<siteID>123456</siteID>
</securityContext>
</header>
<body>
<bodyContent xsi:type="java:com.webex.service.binding.user.SetUser">
<webExId>bsmith</webExId>
<schedulingPermission>jdoe</schedulingPermission>
</bodyContent>
</body>
</serv:message>
And then the meeting would be scheduled with:
<serv:message xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:serv="http://www.webex.com/schemas/2002/06/service">
<header>
<securityContext>
<webExID>jdoe</webExID>
<password>letmein123</password>
<partnerID>123abc</partnerID>
<siteID>123456</siteID>
</securityContext>
</header>
<body>
<bodyContent xsi:type="java:com.webex.service.binding.training.CreateTrainingSession">
<telephony>
<telephonySupport>NONE</telephonySupport>
</telephony>
<accessControl>
<sessionPassword>1q2w3e4r5t</sessionPassword>
</accessControl>
<schedule>
<startDate>07/22/2013 00:00:00</startDate>
<hostWebExID>bsmith</hostWebExID>
</schedule>
<metaData>
<confName>Test</confName>
</metaData>
</bodyContent>
</body>
</serv:message>
In general, for others operations, the admin account with the scheduling permissions would be used in the security context to authenticate the request and user account in the body.