Your schedule is set on the timezone you were located in when creating your or last editing that schedule. For instance, If you were in Spain when creating your schedule then it will be based on Spanish time. If you then travel to Greece and access your availability schedule, it will be displayed to you in local Greek time which is one hour ahead, however, it will still show you available in Spain at the same original hours when creating the schedule.
To better explain this, if your original schedule was showing you available between 6-10pm Spanish time, then when you access your account in Greece you will see your schedule in Greek time from 7-11pm (one hour ahead) but this still means you are available 6-10pm in Spain. If you want to work 6-10pm Greek time you will then need to edit your schedule(s).