Updating Taxes for selected Product via Api

I am a POS developer and working on Api integration with Poynt.

I am not able to update the taxes for selected product using Poynt Api. Can you please help me on that? Also send me the Curl Json sample for updating taxes for selected Product Id.

I also noticed that updated product price is not reflected in catalog item and takes time to display updated price on Catalog item. How much time it takes to update the price?