You mean recharacterize, not convert. Whether or not the resulting traditional IRA contribution for 2019 is deductible will depend on whether or not you or your spouse is covered by a workplace retirement plan, your filing status and your modified AGI for the purpose.
I think you mean recharacterize (treat the Roth as a Traditional IRA contribution as if the Roth contribution never happened), not convert - a Roth can never be converted to a Traditional IRA.
Yes you can have the Roth IRA trustee do that and move both the Roth contribution and any earnings attributed to that contribution to a Traditional IRA prior to the July 15 due date (or Oct 15 if you file a timely extension). The IRA trustee would issue a 2020 1099-R reporting the recharacterization next January.
It would be deductible if you otherwise qualify to deduct it.