Change Board Type from KanBan to Scrum?

[LALITH BHUVANESWAR MANCHIKANTI]

In our project, we use multiple issue types (e.g. Defect, Task, Change Request) and our team members keep changing the issue types as we get more clarity. 

Please let us know how do we get the list of defects/tasks/change requests that changed over a period of time.

[Nic Brough -Adaptavist-]

To answer the question in the title:  You don't.  Create a new board of  type Scrum.

To answer the unrelated question in the body: run filters that use "issuetype was" clauses