How to do selective @PostUpdate in JPA.

Question

• I have a child entity say X whose parent is say Y.
• X has @PostUpdate defined for it.
• say i remove 'X' from it's parent Y but do not delete X in itself.

• I reattach 'X' to 'Y' causing X's @PostUpdate to be called.

  I do not want to call it in this case. Is there any way I can stop it from happening