No. Enabling Prefix RFI Numbers by Project Stage is irreversible, and Procore shows a confirmation dialog for that reason.
The setting lives on the project level RFI settings page. It adds the selected project stage to RFI numbering. Do not assume it behaves like a preference you can switch on temporarily and reverse later.
Agree the numbering convention before enabling it. On an existing project, review the RFIs and their assigned stages first: RFIs with a stage can receive the prefix, while those without a stage do not. Confirm that this is the intended numbering scheme before accepting the change.