I don't know how you block dates in Aworka. You can mark it as time off but it doesn't actually block it. Maybe email Chris to find out if it's possible? If it is let me know because I would be interested also. Ironically I think you can block dates in George!
To shift everything forward though on Aworka, go to the first date you want to shift, click the little curvy arrow and select 'all' on the dropdown. This will include any jobs you have agreed arranged dates for though. So you might want to shift them manually afterwards to where they need to be.