Work calendars - netsuite oneworld issue and how to do changes in employee hours

In Netsuite oneworld - where netsuite users have multiple companies / subsidiaries - situations arise where employees work at different times for different subsidiaries.

In the existing netsuite functionality employees have a standard work calendar.

However,

1. I don't see how to "switch off/switch on" the calendar to signal periods where the employee is working for one entity or another. The probem here is the employee utilisation reports show the employee is available to work for two entities when they are only available for one.

Any suggestions for a workaround?

2. A similar issue, not related to oneworld,... when an employee switches from full time to part time, how do i change the work calendar in a manner where before a certain date there work calendar was full time and after a date it is part time?