In most warehouse operations - especially in rack pick locations - best practice is to keep one pallet per pick face whenever possible. The reasons are mainly:

Safety - Multiple pallets in a single location can force pickers to reach awkwardly, use unsafe footing, or maneuver equipment in tighter spaces. That increases injury risk and product damage.

Efficiency of picking - One clean, fully stocked pallet is quicker for pickers to work from than having to navigate around two separate pallets or partials.

Inventory control - Having product split across multiple pallets in the same location can cause mis-picks, counting errors, or confusion about which pallet to pull from.

That said, there are exceptions - for example, if your WMS can track sub-location inventory accurately and your racking is designed for double-pallet storage safely, then swapping in a full pallet can save restocking time. But that's more common in bulk or reserve storage, not active pick faces.

In most case-pick or split-case operations, the lean approach is:

Break down the reserve pallet into the pick location until it's full (piece by piece or layer by layer).

Store the empty pallet in the pallet return area or reuse it for the next task.

This keeps the pick face clean, safe, and consistent - and your replenisher's "extra" work is offset by fewer hazards, better picker flow, and fewer mis-picks.

If your supervisors are split, you might run a short time-and-motion trial comparing piece-fill + pallet return vs. full pallet swap with two pallets in the rack. That way you have data, not just opinions, to decide.