I'm trying to use Office Graph with Graph Query Language (GQL) and SharePoint Online Search as per this MSDN article: https://msdn.microsoft.com/en-us/office/office365/howto/query-office-graph-using-gql-with-search-rest-api#available-action-types
For my office 365 environment, I can get data for myself using ACTOR(ME) in the GQL and even for another user using ActorID as ACTOR(21223), where 21223 is an actor ID for a user (for example).
In this case i know Actor ID before hand, but how do I get the ActorID for a given office 365 user? Is there a way to get actor Ids for all office 365users?