IF  EXISTS (SELECT * FROM sys.foreign_keys WHERE object_id = OBJECT_ID(N'[dbo].[FK_tblDokTransSzcz_tslNryZlecen]') AND parent_object_id = OBJECT_ID(N'[dbo].[tblDokTransSzcz]'))
ALTER TABLE [dbo].[tblDokTransSzcz] DROP CONSTRAINT [FK_tblDokTransSzcz_tslNryZlecen]