How to change association via microflow?

I have an entity for a list of tasks. This entity associated with the Administration.Account entity, this way I can assign users to the tasks. - I need to implement the following: - User can request to be assigned to the task. I’m trying to implement it using 3 steps written below, I have a problem with the last 3rd step:   I associated the tasks entity with the Administration.Account entity, this way I can assign users to the tasks using the reference selector. In each list item, there is a "request assignment" button, when User clicks on it, his username is added to the "requester" parameter of this item. When Admin approves a request, a microflow should loop through the list of users and find the user with the same username as the requestor, and associate this list item with this user.   I don't know how to implement the 3rd step - how to find a user with the same name and change association of the list item to this user. I'm trying XPath for it, I would be very grateful for the help. Thank you in advance! --- UPD I tried to get the account of the user, whose name is the same as I store in the “requester” string parameter, but I get this XPath error, how can I fix it? Domain model looks like this:    
1 answers

If the user name is set you should be able to perform a retireve from database with the xpath like so:

Retrieve the account entity object, make sure the retrieve is set to retrieve the first object only and then set the xpath to something like below.

[name = $task/requestor] assuming the name of the requestor is in an attribute.