You cannot delete the header table of a rapid application - how to refresh it?

Hello,

I recently created a RAP (Rapid Application) from a DB table, I had to change the structure of this table (including one of the key fields) and now I'm trying to edit the existing RAP in step 2 (DB Model). What I'm doing is selecting the existing table and clicking on delete (to re-add it later so that SAP reads the latest structure) but I can't delete as I get error message:

Do you know how to make the rapid application to refresh the structure of the DB table and get the latest? Is this even possible? Or I'd rather delete this RAP and then create a new one?

Thanks.