the purpose is that i have to show some values in a selection field , i get the values from webservice. So after doing some searching i find out that i cannot change the values of a selection field after onchange event so i did change the field for type many2one and save the data to database after calling the webservice in onchange method. for now 50% is ok but i need to delete all record of many2one field before calling the webservice. this is the purpose Mr Akhil, i hope that you didi understand me well.