Moving on the 17th of October, mechanic comes on the 20th, can this be sooner?

Hello @Cagdas and welcome here :)

In general it's not possible to reschedule an appointment to an earlier date because the mechanic is usually plannend on the same day your signal will become active. Of course I would like to take a look for you to see if there is anything possible but I'm afraid I will have to disappoint you :( If you fill in your forumprofile I can have a look for you! Can you give me a sign when you filled in your profile? Thanks in advance.