I was forced to change the collation sense a crap application didn’t support Latin1 collation. First I was sure that I needed to reinstall wholes SQL server with the correct collation. But after som googling I recognized that this is possible to do if I rebuild the systemdatabases. In books online you can find the solution to run the following setup command:
Setup /QUIET /ACTION=REBUILDDATABASE /INSTANCENAME=InstanceName /SQLSYSADMINACCOUNTS=accounts /[ SAPWD= StrongPassword ]
But when it comes to cluster you have to know these things before running the rebuild command.
1. You have to run it from the cluster node who is holding the instace.
2. The instance name shall not be written with servername\ instansname. Only the instancename shall be here.
Setup /ACTION=REBUILDDATABASE /INSTANCENAME=xxxxxxxx /SQLSYSADMINACCOUNTS=xxxxxxxxx /SAPWD=password /SQLCOLLATION=Finnish_Swedish_CI_AS