I’m not sure I understand the question correctly.
By “<i>I want to add a name of a location to a field that is a drop down list of locations</i>” you mean that you are going to INSERT a new record in the table that stores the location names ?
Anyway, keep in mind that ‘queries’ don’t store any data. They are just the definition of an SQL statement that will be executed every time you run the query, so if the change you are going to make affects the data returned by the query, then the next time you run the query it will reflect the changes you made and will show updated data.
The definition of the query won’t be updated though.