Yes - Merlin Passholders can click here https://www.altontowers.com/tickets-passes/day-passes/pre-book-passholder/ and pre-book Theme Park entry for £1 per Passholder. Every passholder in attendance must pre-book their admission and present both the reservation and their valid Pass at the turnstiles. Under 3s must also pre-book admission.
Please be advised that regular exclusion dates apply as per your Pass terms and conditions.