After you file

Can the $5,100 be recharacterized to a Roth IRA?  The $5,100 is in a Traditional IRA account that has had deductible contributions in past years prior to 2018. Or, is it it better to simply leave the $5,100 in the traditional IRA and maintain the most current 8606 form that was completed and withdraw funds from the traditional IRA when eligible and without penalty?