Do not need Reported By field as mandatory when creating a change request

I am doing some enhancements on MOC - Change Request Create. I have to make Reported By field not a mandatory one. I made it in the class

/MOC/CL_UIXI_ISSUE_ROOT->ADAPT_FIELDS method. but it is still giving error 'Before you can save the change request you must enter a reporter' when I save. Please someone help me in avoiding this error.