How Pakistan can play an effective role in recent Iran-US conflict?

By playing a role of mediator.

Explanation:

Since we know that Pakistan and Iran both are Islamic countries, and Pakistan have a good relation with Iran. On the other hand Pakistan is also a good friend of us. so by taking both countries to a peace dialogue level Pakistan can play a role in resolving the Iran-us conflict.

Pakistan will not be party of any move that disturbs the peace in the region and will not take sides in the US-Iran conflict.