Warning: The reference operation set is already in use.

What causes this issue?

You are attempting to change a reference operation set that is
referenced in other task lists. These task lists will also be changed
if you make changes to this reference operation set.

How to fix this error?

Check what effect changes to the reference operation set will have on
the referenced task lists. Use the where-used report for task lists.
In routings, select the menu options <LS>Reporting -> Where-used ->
Ref. operation sets</>.
<DS:TRAN.CA90>Execute where-used list</>

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