There was no body text included in you post. Were you using Internet Explorer? The support portal's software vendor, Zendesk, is progressively withdrawing support for Internet Explorer so this may be the root cause if you had tried to post some content.
However, extrapolating from the title of your post: The purpose of the Calculate Workdays node is to calculate the number of whole workdays between two dates. The node itself cannot be modified to generate working hours but if you have a standardized number of hours in a work day then you can simply use a Calculate Fields node to generate the number of hours:
