I know how to change endpoint for each test, but I have 100+ tests so I would like to select project/all tests and say set new endpoint. Is it posible?
Yes it is possible!
Double-click on your WSDL interface in the Navigator view on the left.
Then select the second tab called Service Endpoints. Select the desired endpoint (or add it first via the "+"-symbol) and click Assign. There you select All Requests and TestRequests.