No problem.
When it says to edit related records, that�s is really not what it means. Mits just worded that way to help new usesrs.
It can edit any set of records as define by the matching criterial in a Report Link field.
As we know, you don't need a Relationship have a Report Link field. You can make one yourself. So make a Reportblink field from the record to itself. Ie match on Record ID# in the left, and on the right side navigate all the way back to your same app, and same table and the same Record ID#.
So obviously, there is only going to be one matching record, the record you are sitting on.
Now, be sure in your conditions for firing that you do not create a loop. Because when the Action fires, it is an edit which could cause an action to be fired, which edits the record and triggers the Action to be fired, which edits the record .... you get the idea.
That in fact is why edit the same record you ar on, was not released as an obvious possibility when that launched Actions a few months ago,. How to prevent many users from making lopping Actions. They willl time out after 10 loops by the way. The max rate is 10 per second and then they max out and throw an error by email.