While consuming webservices how to change language of the session?

When we are using webservices over classes and representations we get the list of items with this call:

https://SERVER/api1/x3/erp/FOLDER/ITMMASTER?representation=ITMMASTER.$query
That's ok.
But how do I inform that I want to change the language for another call?
In the normal access in the browser path we can see the call like:
http://SERVER/syracuse-main/html/main.html?url=%2Fsdata%2Fx3%2Ferp%2FFOLDER%2FITMMASTER%3Frepresentation%3DITMMASTER.%2524query%26profile%3D~(loc~%27en-US~role~%27c614aa1a-6990-47a6-80be-8ab4e928096b~ep~%27e067ae68-2f24-45bf-9678-abd5c214751e~appConn~())
There we can see the locale being defined, how can this be done using a webservices api client?
Thanks!