I want to disable auto cancellation for all reservations

It is not possible to disable auto cancellation for all reservations.

However, you can virtually disable auto cancellation by setting long auto cancellation time.

Click [App settings] > [ACALL MEETING] in the side menu on WorkstyleOS Portal, and set long auto cancellation time in the "Time Setting" section.

NOTE
・For details of auto cancellation time, please refer to [Set Automatic Cancellation Time for Meeting Room Reservations].

I want to disable auto cancellation for some of the  reservations

It is possible to disable auto cancellation for only some of the. reservations.

You can choose enable or disable auto cancellation when creating each appointment/meeting.

Please refer to [Set Enable/Disable Auto Cancellation for Each Appointment(External/Internal)] for the details.