Steps to remove/eradicate project concerns:

1.	Collect all/basic the details of the project in concern.
2.	Find out in which task client’s concerns/dissatisfactions are there.
3.	Gather and analyse the client’s dissatisfaction/concern and deduce his requirement(output we have to achieve and show to client).
4.	Discuss with your subordinate who is currently working on the project about how to achieve that requirement/output.
5.	If the subordinate currently working on given project is a new assignee, then contact the subordinate who has worked in the given project for long time or from the initiation phase or the one who has enough knowledge/experience in the project platform/language. Let’s call this person a senior/mentor subordinate.
6.	Instruct/suggest the current subordinate to take advice/guidance from the mentor subordinate and get the given issue/concern resolved.
7.	If the current subordinate is still unable to resolve the issue/concern, then assign the issue/concern to mentor person, not before relieving him from one of his current project so he can induce time & efforts in the concerned project.

Note:
There can be more than one mentors, so the concerned project can be assigned to anyone of those.
Same above steps can be applied to minor/major tasks too.