batch update specified requests?

A challenge for you: I am scoping a reimplementation of our Servicedesk Plus installation. It has been incorrectly and badly used in the past so I need to assess whether to start completely from scratch with a clean install or clean and reconfigure the current install.

We're talking about 56.5k existing tickets so it's not a small scale project...

If I provide a data dump of all requests that have a request status that is not 'closed' would it be possible to batch update them to 'closed'? There are currently c.5,500.

If I can find a way to achieve this it would make the reconfiguration task much more manageable. Without the issue of the requests that have not been closed I can progress much more quickly!

Thanks for your soonest feedback,

Angela