The CHGPRTF is as follows:
CHGPRTF FILE(QSYSPRT) EXPDATE(*DAYS) DAYS(45)
When issuing a
CHGCMDDFT CMD(CRTPRTF) NEWDFT('EXPDATE(*DAYS) DAYS(45)')
I get a CPD6263
Checking between parameters not done for parameter EXPDATE.
I created a PRTF anyway and it has EXPDATE(*NONE) - the IBM default.