Due to my technician is not convenience on May 15th. Could it possible to postpone the arrival date to May 18th? For the service, we will absorb the hotel cost as the same so please amend the daily rate to EUR 850. When compared with previous invoice 949854 dated 18.02.2015, it seemed some cost increasing such as Travelling day, Ticket and Adjoining cost. Can you charge us as same price as invoice 949854? Advise please