How to use sensor value as entity_id in call service node

I am playing with Alexa Actionable Notifications and have the basic flow written and working. What I am struggling with is how to use a sensor value as the entity_id when the flow decides which media_player to use for the call service node. Instead of defining a fixed value for entity_id, I would like to use the sensor.last_alexa entity to determine where a person is responding to the Actionable Notification.

[{"id":"ab0fdc89.8b28a8","type":"server-events","z":"bc5d2546.59a7a8","name":"Alexa Notification Response","server":"79e1f09.1e9b71","event_type":"alexa_actionable_notification","exposeToHomeAssistant":false,"haConfig":[{"property":"name","value":""},{"property":"icon","value":""}],"x":160,"y":1720,"wires":[["b46904c8.42d7c8"]]},{"id":"b46904c8.42d7c8","type":"switch","z":"bc5d2546.59a7a8","name":"Notification Check","property":"payload.event.event_id","propertyType":"msg","rules":[{"t":"eq","v":"actionable_notification_music","vt":"str"}],"checkall":"true","repair":false,"outputs":1,"x":430,"y":1720,"wires":[["cdaf68ed.077f78"]]},{"id":"cdaf68ed.077f78","type":"switch","z":"bc5d2546.59a7a8","name":"Notification Response","property":"payload.event.event_response","propertyType":"msg","rules":[{"t":"eq","v":"ResponseYes","vt":"str"}],"checkall":"true","repair":false,"outputs":1,"x":660,"y":1720,"wires":[["dc84a6df.f0f048"]]},{"id":"dc84a6df.f0f048","type":"api-call-service","z":"bc5d2546.59a7a8","name":"Play Pandora (Last Triggered)","server":"79e1f09.1e9b71","version":1,"debugenabled":false,"service_domain":"media_player","service":"play_media","entityId":"sensor.last_alexa","data":"{\"media_content_id\":\"pandora\",\"media_content_type\":\"routine\"}","dataType":"json","mergecontext":"","output_location":"","output_location_type":"none","mustacheAltTags":false,"x":930,"y":1720,"wires":[[]]},{"id":"79e1f09.1e9b71","type":"server","z":"","name":"Home Assistant","legacy":false,"rejectUnauthorizedCerts":true,"ha_boolean":"y|yes|true|on|home|open","connectionDelay":true}]

I detect motion in my office, turn on lights, etc and then I ask if I would like to listen to music. When I respond “yes”, I then fire a call service node to play music on media_player.office. Instead of having five different flows to handle each media_player, I would like to pull the data from sensor.last_alexa and present as the entity_id.

sensor.last_alexa is automatically set to the last Echo that had an interaction.

SOLVED!

I found this in another current topic.

Thanks, @Kermit