Flying to NAN tomorrow, booked my return on a separate PNR the next day.

Very annoying I cannot OLCI because they are not able to be linked/system does not recognize the return ticket!
Without bags it is much easier to arrive late and head straight to gate, don't want to miss check in closing which is around T60 I am told (no bags).

Any suggestions? I tried to get NZ agent to cancel and then rebook both flight under same PNR but wouldn't work.
Annoying.