Hi Ashwan,
Thank you for contacting Syncfusion support.
We have prepared the sample for your requirement which can be viewed form the below link.
In the above sample, initially work hours from 9 AM to 5 PM is highlighted and when the button is clicked work hours will be highlighted from 10 AM to 12 PM. Please let us know if you need any other further assistance.
Regards,
Karthigeyan
