How do I adjust the water pressure in my Glacier Bay Roman Tub Faucet 478 064?

How do I adjust the water pressure in my Glacier Bay Roman Tub Faucet 478 064?

You don't! The house PSI determines the pressure coming out of all your faucets. Is your complaint that all the faucets have good pressure except Glacier Bay faucet? If not then post back with more details. Regards, Tom

Yes all have good pressure, except this one.

I think your faucet most likely has good pressure but bad volume. Has it always been like this? http://www.faucetinstructions.com/index.html