The procedure of converting shared VPS to hardware node http://download.pa.parallels.com/poa/5.5/doc/index.htm?fileName=74135.htm requires configuring YUM repositories in container:
3. If the container is running RHEL 4 or CentOS 4 you need to configure yum repository on the container. Refer to the instructions provided at http://wiki.centos.org/HowTos/PackageManagement/YumOnRHEL.
Is it possible to do conversion without having repositories configured and configure repositories later?
Yes, conversion process does not strictly need VPS to have yum repositories available - it only checks that yum installed in container by executing command
yum clean all. However, it is recommended to configure yum repositories on managed server as soon as possible to keep it up to date and to avoid potential package dependency problem that may arise during OA updates installation.