BPM - How to use a custom 'delay period' to calculate a reminder date ?

Hello,

I am facing an issue and I don't find any easy way to solve my problem.

I want to know how to, using BPM (no custom code), calculate a reminder date depending on 2 other fields of my record

  • the due date
  • the reminder delay (int value ; number of day for this specific record) 

When I use the BPM date calculation feature, I don't find any easy way to set the reminder date as "due date - reminder delay".

And of course, I don't want to set multiple condition to say "if delay = 1 then ...else if delay = 2 etc." because the delay can be really differents.

Of course, a code solution is easy, but it seems a basic requirement, so I want to be sure that I am not missing something.

Many thanks for your time and your help,

Fred