Hi Divyapriya,
Try setting "Field Properties" as "Standard" only both at "Entity Types per Change Request Step" and "Attributes per Change Request Step" for your Change Request Step at config level.
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After that, please try implementing the BADI USMD_ACC_FLD_PROP_CUST_DEP_SET
and use MODIFY_FLD_PROP_ATTR to set out the attributes as Read only.
