Method of concrete designing in STAAD Pro as per IS 456:2000

Dear members. 

Greetings to all.

I am having a question that, when the STAAD starts designing the concrete sections which method it will follow. Like "Limit state method of design" or "Working stress method?" as per Indian Stranded 456:2000

If there is an  option to specify to STAAD to design in Limit state or Working stress method  please let me know.

Thanks in advance