Oracle Solution for Error ora-14284

ORA-14284: one or more of table's subpartitions reside in a read-only tablespace

What triggered the Error:

User issued ALTER TABLE statement attempting to modify an existing VARCHAR2 (or VARCHAR) column to be of type CHAR (or CHARACTER), increase length of an existing CHAR (or CHARACTER) column, or add a column with user-specified default for a table one or more subpartitions of which reside in read-only tablespaces, which is illegal

What should we do to fix it:

Avoid performing aformentioned operations on a partitioned table one or more subpartitions of which reside in read-only tablespaces