phase jump to function phases

Hi.

  in UVM, It is legal to have phase jump to any function phases.  but it seems in below demonstration code it does not work as I expected.  I expected the flag build_agt2 = 1 after the phase.jump(build_phase).

    class mycomponent extends uvm_component;

      .......

     bit build_agt2;

     function void build_phase(uvm_phase phase); 

           `create_agt1();

           if ( build_agt2)  

              `create_ag2() ; or

              // `override_agt1_by_agt2();  

     endfunction

    task run_phase;     

             // change flag build_agt2 to 1;

   endtask

   function void phase_ready_to_end;

          // if the imp phase  is in shutdown_phase

          // then phase.jump to build_phase

 endfunction