change case state to work in progress Api (In genesys)

[Research]

Hi

Has anyone help me to find the correct Api Method
Genesys is integrated in instance

when ever a user call 
The call will routed to servicenow and his case record should move to Work in progress.
The case state should change to work in progress.
for this I want to know which Api is used in genesys cloud

Please guide me
Thanks.