Passing constants at runtime

[MaddyMS]

We have a lookml which uses a constant name for a project .. 

lookml sql code -

sel * from @project.table

just trying to see how I can parameterize/override the default with user input? 
I want to keep the default as is,  but enhance the dashboard to accept user project value at runtime and run the sql for new project  ..

Appreciate your help!