I love using the internet for research!
I use the OTRS open source ticket system to manage IT projects including help desk requests. Today a tech put in the wrong amount of time. Instead of 0.50 hours, it was entered as 50 hours. How to change it? There’s no place to correct that time. Any additional comments add to that time rather than editing it.
I found the solution on otrs.org
There’s the solution! Enter a new note or comments with a negative time.
For example, with it reporting 50 hours, enter a ticket with the time as -49.5. It will do the math and report the time as 0.50.