No, you cannot be the primary account holder for both the Chase Sapphire Preferred® Card and the Chase Sapphire Reserve® at the same time.
Chase’s eligibility rules prohibit current Sapphire cardmembers from applying for a different Sapphire card.
Additionally, individuals who have received a new cardmember bonus on any Sapphire card within the last 48 months are ineligible to apply.
Specifically, the terms and conditions state:
But if its been more than 48 months since your last Sapphire Preferred or Sapphire Reserve welcome bonus, you could downgrade the card to a card like the Chase Freedom Unlimited®.