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That’s what the error directive Resume allows you to do. First, you use a Search module to see if it exists, then Create a new item if it doesn’t exist. In the Create field, you use an if-statement to “ignore” a required field if there are search results, throwing an error and allowing you to “skip” the creation module.
The if (not-exist-create-ignore) throws the error (ignore if exists), which the Resume directive can be used to return the item from the Search module (to check if it exists).
I explained this in a similar older post Can I skip a module based on a filter? - #3 by samliew