If you or a team member needs / need any help during my vacation, please do not hesitate to contact me on my mobile phone.
Should I write need or needs?
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Sign up to join this communityIf you or a team member needs / need any help during my vacation, please do not hesitate to contact me on my mobile phone.
Should I write need or needs?
In this case, I would go with "needs" like SarahT mentioned in her answer.
Generally, when we have two or more singular nouns or pronouns that are connected by or or nor, we use a singular verb.
Therefore, I would say
If you or a team member needs any help ...
And when we have a compound subject that contains a singular and a plural noun or pronoun connected by or or nor, we use the verb that agrees with the subject that is closest to the verb. This is what James K referred to in his comment.
If the second subject was plural (= team members), then I would use the plural verb:
If you or your team members need any help ...
The Chicago Manual of Style (CMoS) 17th ed. says
When a verb has two or more subjects connected by and, it agrees with them jointly and is plural {Socrates and Plato were wise}. When a verb has two or more subjects connected by or or nor, the verb agrees with the last-named subject {Bob or his friends have your key} {neither the twins nor Jon is prepared to leave}. — 5.138: Agreement in person and number
This problem may also arise when using an either-or or neither-nor construction. The CMoS says that
... pronouns joined by or, either–or, or neither–nor are traditionally said to take the verb form that agrees with the nearer subject {either he or I am in for a surprise} {either you or he is right} {neither you nor I am a plumber}. — 5.143: Agreement in first and second person
The "supplemental materials" link in this APA Style Blog says
When the subject is composed of a singular and a plural noun joined by or or nor, the verb agrees with the noun that is closer.
The APA and MLA style guides say the same thing, only I can't quote them because I don't have full access to them. You can look them up online.
When joining a list of singular nouns with "or," use a singular verb. "If you or a team member needs any help..."
The rule is that the verb in an or, either/or, or neither/nor sentence agrees with the noun or pronoun closest to it. (source)
As the verb follows "a team member", it should "needs":
If you or a team member needs any help...