Unable to update the Reason and Reason Text to Null in Adjustments Window

Hi All,

We are unable to update Reason field into Null in Adjustments Window when manually applying the discount via Modifier. The user try to apply modifier at Line level manually, the Reason, Reason text fields are defaulted with Value of “Manually applied adjustments”  and It takes value Manual from oe_lookups  and lookup_type is CHANGE_CODE. When user is trying to update for Reason  and reason text fields into the Null but it’s re-defaulting  value again  with “Manually applied adjustments” when saving record , So We are unable to update Reason to Null.  So here i need clarification on below points.