Znuny Open Source Ticketsystem

Is there anyway to change a setting so notes added to call are editable.
On ocasions I have posted a note and accountable time to wronge call is there anyway to delete this note or edit it?

Thanks for the reply,
Justed created a dummy ticket and put in a negative amount this works.

I run a small IT Consultancy business and use OTRS as a mean to log calls for my customers and enter in the time spent on each job. On some ocasions the account time exceeds what i want to actually charge the customer. Is there any way to make accounted time editable so the accounted time can be ...