How do I get a passport stamp if visitor center was not open when I was at white sands in New Mexico. Passport cancellation stamp

The visitor center was open but only allowing a few in at a time. Other parks we've been to this week have the stamp outside and or a park ranger there with the stamp.

I would call and see if there is a virtual stamp that you can get for the location.

Passport stamps were available at almost all 52 parks and Monuments even if the Visitor Center was closed... on a table outside the Centers

I know some parks are leaving a stamp outside due to covid hours