Can I use form-data in a REST call dynamically?

Hello, We are using the Mailgun e-mail provider to send e-mails. Mailgun requires us to use form-data. However, in Mendix we need to specify the exact key-value pairs, otherwise we get the error that one of the parameters is not valid when it is empty. But the problem here is that we always require a 'To' paramater, for example (the e-mailaddress to which we send), but the 'cc' parameter might not always be used (see image). Is there any way to be able to do this dynamically or work around this?  Thanks.
1 answers

You can create two separate restcall actions. One with and one without the ‘CC’ parameter. Then use a split in the microflow to decide which one to use.