I assume you are asking about your grandmother's niece. Do you have your grandmother's first name, maiden name and married last name? Do you have her birth date and location, such as country, county and city?
Keep asking questions as there are many at WikiTree who like to answer questions.
As far as the Lambert surname, there are over 11,000 with that Surname listed at WikiTree. To find other names at WikiTree, just click on Find. Find is at the upper right of this page. After that menu opens up, click on Surnames. Then, enter any surname you like. There is also room for first names.