[{"_id":ObjectId("62c2e94e65f32725f8f62b79"),"requestid":"123456789","iscancelled":true,"organizationid":"3","instanceid":"172","offerid":"offer123","promotionid":"promo123","jobtype":"portaljob123","jobid":"job123","requeststatus":"began"}]

db.collection.update({requestid:"123456789"},[{$set:{requeststatus:{$concat:["$requeststatus","-","tigger_datalink stopped since request was cancelled"]}}}],{$multi:true})