Rest API gives incomplete list of transitions

[JAcek Ok]

Hello,

On Jira Service Management Server, I'm trying to find a way to move a Request from "In progress" to "Pending" via REST API. I've been using the calls described in https://docs.atlassian.com/jira-servicedesk/REST/4.21.0/ and it seems that, first of all, I can check possible transitions for a given issue by:

curl -H "Authorization: Bearer {TOKEN}" -H "X-ExperimentalApi: opt-in" -X GET -H "Content-Type: application/json" {URL}/request/{ISSUE ID}/transition

However, it seems that the list of possible transitions does not match the list of available options when the request is accessed via the Dashboard. 

For example, when the request is in progress, the possible options in the Dashboard are "Resolve this issue" and "Cancel request" what matches the possible transitions shown via API:

"values":[{"id":"761","name":"Resolve this issue"},{"id":"901","name":"Cancel request"}]}

However, when the request is moved to "Resolved" the dashboard shows the option "Back to in progress", but the API does not show such possibility:

"values":[]

It's similar also for other statuses (in a nutshell, it seems to never give the option to move it to "Pending" or "In progress"). Why is the scope of possible transitions not always in line between dashboard and REST API?