Hey hazel_chua
Just a follow up to what the other people have stated.
I've noticed a couple of people have raised similar posts on the forum recently. I've used Katalon browser plugin (which supports front end capture/playback automation) but never Studio but I've done a little reading and it appears Studio includes an API testing component. I'm guessing you're talking about API tests in REadyAPI!/SoapUI and extracting those into the API testing application within Katalon Studio?
The issue people are going to have exporting a ReadyAPI!/SoapUI .xml project file to use in a different tool or vice versa is that the underlying ReadyAPI!/SoapUI project .xml is obviously customised for ReadyAPI!/SoapUI and so wouldn't be interpreted correctly by a different tool if you were to import the project file into another tool.
As far as I can tell - you'd need to develop a bespoke exporter that maps the apis/testsuites/testcases/teststeps to something that would be interpreted correctly by the tool you'd be importing the file into. Even then - ReadyAPI! has some standard types of test steps - REST & SOAP requests, Delays, etc. - but it also has some additional test steps that are less 'standard' and you'd need to map these 'non-standard' test steps to the equivalent in the tool you'd be importing the ReadyAPI!/SoapUI project into - it would be a big job and probably time prohibitive relative to how much work would be involved to just create the tests manually in the new tool.
I suspect you'd need a different exporter/importer tool for each different application you'd intend to import the ReadyAPI! project into.
The only thing you could currently extract to export from REadyAPI! to import into another tool would be the APIs from within the project .xml file. You could extract the API detail by extracting into an openAPI/swagger file that could be then imported into any tool that supports the particular openAPI/swagger .json file - HOWEVER - this is only the APIs - the testsuites/testcases themselves wouldn't be extracted in the .json file - so doesnt help you in the slightest.
Ok - that's all I got - sorry I couldn't be of more help!
nice one
rich