order guide,catalog item

[TEJAS]

I have created a order guide in that i have 2 catalog item
create new 
update 
in the both form all field are same 
example: If i created a record test123(which is mapped to (cmdb_ci_service_discovered)
and i want to update that record test 123 in that only only few field i want to change other should remain same this is happening to me but 
The problem is in (cmdb_ci_service_discovered) table the ownedBy field is sys_user
but in the form we need user change approval group 
in update form the owned by field to sys_user_grmember and in filter i have given group is change approval group

but when i fill update form if i need to update owned by its getting updated but if i don't need to update owned by and update other field at that time owned by field is empty so it is updating as empty in the record also 
below i have attachments

[Dnyaneshwaree]

Hello @TEJAS  ,

You can try this by adding script logic in such a way that, you can check if the update form provides a value for required fields(for each field) using "if " condition. if yes then use the value from the update form else  no change (Blank block).