OData query options

I am new to Blackbaud Sky API and am experimenting with some Appian Integrations. The following is a Get Constituent List call.

GET "https://api.sky.blackbaud.com/constituent/v1/constituents?constituent_code=Donor"

Returns many constituents but I only require a few select properties like first and last name. I try to append

<span><span><strong>"?$select=first,last</strong>" to the call but it is ignored. How can I append this or is this not possible in Sky API?<br /><br /><br/>I could not find documentation on OData query options in Sky API Developer site. I am looking for a documentation<br /><br /><br/>similar to MS Graph's </span></span>https://docs.microsoft.com/en-us/graph/query-parameters?view=graph-rest-1.0


Thank you,


Med