Change pool tax_ratio

[Gary6502]

made a mistake when I set the tax_ratio. I've looked through the wiki and searched the posts but most seem to point to changing the metadata. The tax ratio is in the createStakePool_output.txt so apart from recreating another stakepool certificate how do I only update the tax ratio?
Also if another stakepool cert has to be created, how do I get the previous tADA back or is it the cost of doing business? Since I want to keep the same pool ID and name do I still need to re-register at the Cardano foundation since the metadata hasn't changed? Thanks!