Using JSON API as a certain LDAP user

We have a situation where we need to insert records server side, but as a certain LDAP user. Our version is set up to allow LDAP/Active directory authentication. We can do this with the code collaborator client on our server, but it's not always foolproof to start and stop the client process. I'd like to use the JSON API instead. Is there a way that I can spoof the user given that I have the user name?

Thanks

Robert