Can a Coinbase transaction be reversed?

Could you please clarify whether it's possible to reverse a transaction that has already been made through Coinbase? I understand that transactions on the blockchain are typically irreversible, but I'm curious if Coinbase, as a centralized platform, offers any sort of safeguard or mediation service that could potentially allow for a reversal in certain circumstances. Additionally, if a reversal is not possible, what are the best practices or steps one should take to ensure the safety and security of their transactions on Coinbase? Thank you for your assistance.