Change management Notifications via email for approvers

[Harshad Bhagwat]

I am a service desk user & have added change management plugin as per this link

https://confluence.atlassian.com/servicedeskserver033/change-management-861255537.html?_ga=2.8649845.1143506908.1590344881-1871970650.1589800024

I am facing with the following issues when I create a change request

1) When I assign a review manager I or anyone else should not be able to change the state except for the review manager. Currently anyone is able to change the state from peer review/manager approval to planning

2) Whenever I assign manager as approver, an email notification should be sent to the respective him/her notifying him that he is been set as an approver and he/she should work on the item. I have set an 

[Nic Brough -Adaptavist-]

1) add a condition to the workflow that says "only the person named in the review manager field can use this transition".  You may need to add an app to provide the function

2) name the "review manager" in the notification scheme, for "issue updated"