We have noticed some of the change orders (e.g. unprocessed orders to switch the service plan, subscription period) are getting canceled automatically by Billing. Why?
This is a new functionality that is implemented in BA 6.0 and in BA 5.5 starting from 5.5.8, please refer to the description of these changes in release notes:
BA 6.0 notes (see description of PBA-53211)
BA 5.5.9 notes (see description of PBA-58427)
This was done to avoid an issue with the change orders stuck in provisioning forever as it used to be in PBA 5.5.x (please refer to the kb #116446 ).
A new change order must be placed.