I have a doubt regarding the use of the verb "has or have " after who in the following sentence,
I request you my work to be evaluated by Mr. Bender and Mr. Joseph who has expertise in the work done by me.
The way it is written now is indeed confusing. The has suggest that only Mr. Joseph has expertise, but then a comma could've been added:
I request you my work to be evaluated by Mr. Bender, and by Mr. Joseph who has expertise in the work done by me.
This would probably not have confused you.
If both have expertise, you must use have.
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As you are referring to two people (in third person) in your sentence, you should use the plural verb have after who. You use the singular verb has after who when you are talking about a person (in third person).