As per 3GPP TS 29.060 version 15.3.0, section 7.3.3, 7.3.4, 7.3.5 and 7.3.6
Only if PCO IE is included in Update/Delete PDP Context Request then it
must be present in Update/Delete PDP Context Response.
In order to reflect on whether the request contained PCO IE or not
the SMF context containing the GTP request needs to be updated
i.e. update if present else clear the contents