Thanks Jahid for the doc links. The first link does indicate I can change the blueprint while doing a bulk import/update, however, I have tried this several times and the blueprint always remains the same. Is this a bug perhaps or a documentation error?
The second link explains how to change a reservation which works fine, but there is no option there to change the blueprint.
As far as I know there is no way to do this except for maybe hacking the PostgresSQL db but I wouldn't do that if I were you.
What we always do is just unregister them with the CloudClient (which is really nice and fast to just de-register VM's from vRA) and then just re-import them with the blueprint. Couple of minutes of work .
Then the only way to do this is un-register the machines from vRA and import them with the dummy blueprint.
CloudUtil.exe Machine-BulkRegisterExport [-b|--blueprint] [-m|--managed] [-e|--exportNames] [-p|--properties] -f|--filename <Value> [-g|--group <Value>] [-i|--ignore] [-o|--owner <Value>] [-t|--machinetype <Value>] [-n|--resourceName <Value>] [-r|--resourceType <Value>] [--repository <Value>] [-sn|--sourcename <Value>] [-st|--sourcetype <Value>] -u|--user <value> [-v|--verbose]
Please use link :-
Please mark as correct if it helps