Hi there,

You can simply got this path language/en-GB/en-GB.com_komento.ini and edit this language string COM_KOMENT_POSTING_AS_GUEST and COM_KOMENTO_FORM_LEAVE_YOUR_COMMENTS

Or you can do language override for those language string as follows https://stackideas.com/docs/komento/administrators/how-tos/how-to-create-language-string-override

Please give it a try and see how it goes.