create a flag if there is a difference between two dates columns

Hi ,

I have a requirement where I want to flag whenever there is a difference between two dates i.e. Promised Receipt Date and expected receipt date in purchase line Table.

If I need to create a cue on the Role center, How can I compare two dates with Flowfield?

In case I want to I want give an error in Red Line just like there is one for "Overdue sales Items"on Role centre.

Thanks in Advance