Uploading sdlxlf into XTM

Hello,

My client wants me to work in XTM for a particular project, but I'd prefer to do the work in Studio 2021 and then upload into XTM. She's sent me files with xlf extension. But she says that my target file with extension sdlxlf won't upload into XTM. Is there a way of saving my sdlxlf file as just xlf, so she can upload it into XTM? Thanks for your advice.

Liesbeth