Summary:

A user has asked if there is a way to convert a secondary entity into a primary entity.

Resolution:

To make an Entity appear as a Primary Entity 

The entities that are shown as Primary Entities in the Administration -> Customisation screen have the field bord_primarytable set to 'Y' in the custom_tables metadata table 

select bord_primarytable, * from custom_tables 
where bord_primarytable is not null 

To promote a Secondary table into a primary entity set the value of bord_primarytable to 'Y' for the entity you wish to promote.