When do cockpit crew change on Triangle Routes?

[Ammar]

AoA guys,

I was wondering on routes like PK733, PK711, PK852, PK771, etc. when does the crew change?

For example, PK749 flies from ISB-MXP-CDG. Does the cockpit crew change at Milan upon arrival, or upon arrival at Paris?

[A310]

There are no hard and fast rules. Most of the times Captains change at the first stop while the FO sits during all the sectors. FOs are allowed to rest during the second sector. This is the usual practice and not any kind of rule.