Hi @ManuMittal
Sadly there is no option to keeponly friday and diable all dates. But there is an option to force user to select friday. You can set up an error message tool such that if the selection is not friday it will pop up a window asking user to select friday. This is part of user input validation. In formula i am checking is today not friday (i,e condition for error & friday is day 5) so if today if not weekday 5 then popup an error else process the workflow.
Workflow:
Case 1: selecting non friday. It pop ups a window asking to select friday
Case 2: Selected friday. Since its friday it processes and proceed to output.
Hope this helps 🙂