How to change question type for the whole block

Could anyone tell me whether I can change question type for all the questions in a block? Let's say, in a block, the original question type for all the questions is "multiple choices", however, I want to change those questions into "slider". Is there an easier way to do that instead of editing each questions one after another? The reason is that since the import txt survey function does not support slider questions, I have to format the question type into "multiple choice" for importing, although, the correct question type should be in slider. I have to import all items in the form of multiple choice questions first, and then change the question type from "multiple choices" into "slider" for all the questions. Thanks for your help!