M:\>sqlplus scott/tiger@ora10

SQL> create table some_table
  2  (id number,
  3   name varchar2(20));

Table created.

SQL> insert into some_table (id, name) values (1, 'Littlefoot');

1 row created.

SQL> commit;

Commit complete.

SQL> $exp scott/tiger@ora10 tables=some_table file=some_table.dmp

About to export specified tables via Conventional Path ...
. . exporting table                     SOME_TABLE          1 rows exported
Export terminated successfully without warnings.

SQL> alter table some_table drop column name;

Table altered.

SQL> select * from some_table;

        ID
----------
         1

SQL> $imp mike/lion@ora10 file=some_table.dmp tables=some_table

Warning: the objects were exported by SCOTT, not by you

import done in EE8MSWIN1250 character set and AL16UTF16 NCHAR character set
. importing SCOTT's objects into MIKE
. importing SCOTT's objects into MIKE
. . importing table                   "SOME_TABLE"          1 rows imported
Import terminated successfully without warnings.

SQL> connect mike/lion@ora10
Connected.
SQL> grant select on some_table to scott;

Grant succeeded.

SQL> connect scott/tiger@ora10
Connected.
SQL> desc some_table
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------

 ID                                                 NUMBER

SQL> alter table some_table add name varchar2(20);

Table altered.

SQL> update some_table s set
  2    s.name = (select m.name
  3              from mike.some_table m
  4              where m.id = s.id
  5             );

1 row updated.

SQL> select * from some_table;

        ID NAME
---------- --------------------
         1 Littlefoot

SQL>