I DON'T WANT TO DELETE THE COMPLETE DATA FROM RECORD BUT JUST THE VALUE FROM LOOKUP FIELD

I DON'T WANT TO DELETE THE COMPLETE DATA FROM RECORD BUT JUST THE VALUE FROM LOOKUP FIELD



But doing this not helping me sole my problem .... actually i don't want to delete the data from second form database  but  from the lookup field i want to remove that value . for e.g . One form is there with name service  challan anED THAT other is job status . In Ist form many fields are there where i enter all the details  of the product n, type etc . one field is job no.  whose value i have incremented automatically .  now this job no. is used AS LOOKUP FIELD IN SECOND FORM . AND DATA RELATED THAT  JOB NO. IS NOW ENTERED IN SECOND FORM .  NOW I WANT THAT ONCE I ADD THE DETAILS RELATED THAT JOB NO. AND SUBMIT THE FORM  THAT JOB NO. SHOULD NOT BE DISPLAYED IN SECOND FORM .  E.G.  THERE ARE 1-10 VALUES ARE SHOWING IN JOB NO, IN SECOND  FORM LOOKUP FIELD . NOW I SELECT JOB NO. 9  AND ENTER THE OTHER DETAILS RELATED THAT JOB AND AS I SUBMIT THE BUTTON . THAT VALUE SHOULD NOT BE DISPLAYED IN LOOKUP FIELD  IT SHOULD SHOW 1,2,3,4,5,6,7,8,10  BUT NOT 9 . .
PLS REPLY ASAP .  THANKS