table restruction

Hello!

I want to restructure a table called study.
this table has the following structure:

Table "study"
Attribute | Type | Modifier
------------------------+------------------------+----------
chilioid | character varying(80) |
instanceuid | character varying(64) |
id | character varying(64) |
studydate | date |
studytime | time |
modality | character varying(2) |
manufacturer | character varying(128) |
referingphysician | character varying(128) |
description | character varying(128) |
manufacturersmodelname | character varying(128) |
importtime | double precision |
chilisenderid | character varying(80) |
accessionnumber | character varying(64) |
institutionname | character varying(128) |
workflowstate | character varying(8) |
flags | character varying(8) |
performingphysician | character varying(128) |
reportingphysician | character varying(128) |
parentoid | character varying(80) |

So , what I have to do is to move the column parentoid between chilioid
and instanceoid. After that operation parentoid is the second column in
the table study.

Can I do any restructuring in the running database or should I dump the
database and create a new changed schema and then put the data from the
dump back?
So this would spent a lot of time, otherwise it works sure.

Is there any oppertunity to restructure the existing database without
using a dump?

Thanks in advance

David