Under EASA rules, you can only have one PIC. If an instructor is giving instructing and you log Dual Received, the instructor logs Dual Given and PIC.
The biggest issue here is when pilots have done training outside of Europe, for example in the USA. Under FAA rules, if you are qualified on the aircraft category and class (and type if applicable), you can log PIC and Dual Received. These pilots must recalculate their totals in their logbook to reflect the correct rules.