Forms - Open New One Depending on Data Entered

[bluedevil]

Hi,

I'm not sure if what I am trying to do is possible, if it is please can you point me in the right direction? I have used Access before, but not the forms and I am getting myself confused!

I have a table tblRecording with the following fields:

Received Date, Action Date, Customer Number, Income Stream, Activity, Reason for Missed SLA

I also have a form frmRecording that has all of the above fields, apart from Reason for Missed SLA. The reason for that is that all fields are mandatory apart from this one, which has to be completed if the difference between the two dates is greater than 3 working days.

What I would like to happen is that if the difference is greater than 3 WD, a new form opens for the user to enter a reason.

My problems are that I can calculate the difference in days, but not working days and I don't know how to use that to get a new form to open?

Thanks in advance for any help you are able to provide.
Paul