from web site
Courier a domestic flight should be an easy task, but even a single error in the passenger's name can become a very stressful situation very quickly. Passengers who booked via Allegiant Airlines often want to know what will be the action taken if the name on their ticket is incorrectly spelled or has to be updated. Since Allegiant is an ultra-low-cost carrier, it has imposed strict rules regarding name changes and will be, therefore, less likely to offer these services compared to full-service airlines.
link:-https://jobhop.co.uk/blog/458036/allegiant-airlines-name-update-policy-for-domestic-travel