ORA-01463: cannot modify column datatype with current constraint(s)

admin

ORA-01463: cannot modify column datatype with current constraint(s)
Cause: An attempt was made to modify the datatype of column which has
referential constraints; or has check constraints which only allows changing the
datatype from CHAR to VARCHAR or vise versa.
Action: Remove the constraint(s) or do not perform the offending operation.