Hello All,
I'm trying to create a project that is dependent on another project.
So both projects have Due Date, and I want them second project Due Date to be dependent on the first one, if the first one Due Date has lets say delayed a 5 days, I want the second project to be delayed the same amount.
I tried to achieve this using automation, but the issue is I don't know how to make changes on a date type value. How would I be able to achieve this?
This use case is pretty interesting and I'm also exploring it a little bit. 
But to answer your question "how to make changes on a date type value", if I understand it correctly, what you need may be a simple solution: =[Due Date] - 5
I haven't tried to build the automation myself, but I think given your description, it can be something like
=Table2[Due Date] + (Table1[Due Date] - $[PREVIOUS])
Let me know if it works for you! 
@prot-60b9, I don't think you need to do this with an automation even.
Here's a sample table I made:
The [due] column gets a column formula:
=if([dependency]<>"", [dependency][due]+[dueShift], "")
And the [dependency] column is formatted as a rowlink, sourced to the same table. Now, whenever there's a dependency, the due column autoupdates. See if this fixes your problem.
