API to trigger a manual or paused step in a pipeline

I have pipelines with build steps that are triggered by commits which build artifacts, followed by a manual single deployment step that deploy those artifacts.  I want to be able to make an API call to trigger the deployment step for a pipeline where the build step has passed and now has state.name="IN_PROGRESS" and state.tage.name="PAUSED". 

I can query the API to find repos with pipelines that are ready to deploy, and we want to automate their deployment based on time and other external triggers/criteria.

I could use custom steps instead of deployment steps, but then we'd lose the nice traceability Bitbucket provides for deployment history.  Also we plan to expand this to deploy to multiple environments (e.g. test, stage, prod)

Here's a simplified version of our current pipeline yaml:
default:

• step:
  script:
• runBuild.sh
  artifacts:
• build/**
• step:
  name: Run Deploy
  deployment: Test
  trigger: manual
  script:
• runDeploy.sh test