Can I change my response headers to contain Content-Type : text/xml; charset=utf-8

For the DPD Push Trackingsystem I need to return an xml like:
<push> <pushid>42</pushid> <status>ok</status> </push>

I have a lambda returning this xml as a string and when I use this as return value of the response it seems that xano api is returning this string like

"<push><pushid>42</pushid><status>ok</status></push>" with Content-Type header of "application/json; charset=UTF-8" instead of text/xml
<push>
    <pushid>42</pushid>
    <status>ok</status>
</push>