I took $30000 from a qualified IRA and put it into a Roth.I know this created a taxable eventcan I reverse this before I file my 2018 or is that transaction irreversible?

had to eliminate spaces to fit in. Here is the full question:

I took $30000 from a qualified IRA and put it into a Roth. I know this created a taxable event but can I reverse this before I file my 2018 or is that transaction irreversible?