It seems to me that I found the solution:

DECLARE @XML XML

DECLARE @ElementName VARCHAR(20)

SET @ElementName = 'city'

SELECT @XML = '

<employees>

<employee>

<name>Jacob</name>

<city>NY</city>

<team>SQL Server</team>

</employee>

<employee>

<name>Steve</name>

<city>NY</city>

<team>ASP.NET</team>

</employee>

</employees>'

--SET @XML.modify('delete (/employees/employee/*[local-name() = "city"])')

SET @XML.modify('delete (/employees/employee/*[local-name() = sql:variable("@ElementName")])')

SELECT @XML