Access HELP mentions "wildcards" for queries. But when you ask for
"duplicates", the implication is "exact matches". It sounds like you want
to find all records for a given company.
You can build a query that includes a prompt in the criterion field, asking
for (a portion of) the company name to be found in the company name field.
See "parameter query" in Access HELP for more information on this approach.
If you combine these two, you'd end up with something like (your syntax may
vary):
Like * & [Company name includes...] & *
to allow you to search for any rows with the text you enter in response to
the prompt being somewhere in the field you put this criterion under
(company name field, right?). WARNING: if you enter simply the letter "o"
in response to the prompt, you'll get every company name with an "o" in it!
By the way, my earlier post still bears review -- if you are entering and
re-entering the text string with the name, different spellings and typos
will mess up your database. Instead, rely on a Person table (or, in your
case, a Company table) and only store the ID from that table. When you
build your parameterized query (see above), use a join between the calls
table and the company table to search by the company's name.