In order to void a ticket from a split PNR, you need the following information (and please make sure to always first go out of the PNR, otherwise it won't work):
- date of issuing
- ticket number
- IATA number
Go out of the PNR and use the following entry:
DDV*17JUL00112345678#N1.1*5720146
Or in case of conjunction tickets, use:
DDV*17JUL00112345678-679#N1.1*5720146