You can shorten or lengthen the shift on your profile at "My shifts" you click on the particular job you want to change and can from here add extra hours on.

See this picture below👇🏼
​

You have three days after the end of a shift to change the working hours, as the payment data will be sent to the payroll company after this. If you register late, there will be a fee of 49 DKK per Chabber for the late registration.

Best regards,
Team Chabber