Date: 201909
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Aircraft: Light Transport; High Wing; 2 Turboprop Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
Airspace: Class E ZZZ
ATC / advisory: Center ZZZ
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Situational Awareness; Confusion; Communication Breakdown
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: In-flight
Contributing factors: Human Factors; Procedure; Company Policy
Primary problem: Procedure

Narrative: I had received a call from Flight Service for a clearance request. We were in an Approval Request status to ZZZ and had some possible delays. I advised Flight Service of these and issued the clearance to Aircraft X with a HFR (Hold for Release). I asked them to standby while I received a time from our TMU (Traffic Management Unit). I was given a XA30Z release time and proceeded to advise Flight Service of this expect departure time. I even clarified Aircraft X is HFR call back at XA25Z and I would work out reference any local traffic. At XA12Z a saw Aircraft X'S code departing off of TEX. Aircraft X called me airborne climbing to 17;000 feet on his IFR clearance. Thankfully; there was no traffic at the time. I asked Aircraft X if Flight Service had released them. Aircraft X advised that Flight Service had not; but that Center had. Aircraft X had called because they heard that the rate into ZZZ changed and wanted a better time. The person they talked with said they could go at XA11Z. Aircraft X said they even clarified if that meant they were released at XA11Z and was advised 'yes'. When I asked who it was they talked with; they said they couldn't really remember the name but told me the phone number they called. I asked my Supervisor to call the number and it rang to our Operations Manager desk. The Operations Manager answered and said he had talked with this Aircraft X and had coordinated with TMU a XA11Z time.  Communication broke down in a big way. First off in my opinion pilots shouldn't be calling anyone to coordinate new times to destination airports. Their company should handle that.  Second any coordinated release times should be through the controlling area/sector not any Operations Manager's. We are using phrases like: Aircraft X 'Hold for release' and Aircraft X 'your release time to ZZZ is XA11Z' or Aircraft X 'expected release time is XA11Z'; often times together to Flight Service. These variations in our clearances can cause lots of confusion especially when you are adding Flight Service as a go between. More and more pilots are asking for Hold for Releases at uncontrolled airports that we can't talk to on the ground and more and more controllers are giving them. In light of the above situation I fell that we should not be giving HFR through Flight Service; myself included. Flight Service should call when the aircraft is close to departing so we can release them or give them an expect departure time. If there are delays we need to have a better way to update pilots at uncontrolled airports that have to utilize Flight Service or Flight Data. The best solution would be standalone clearance delivery frequencies at our busier airports so we can directly communicate with the pilots.




Synopsis: Center Controller reported an aircraft at a non towered airport that had been issued a hold for release called the Operations Manager on the phone was released without approval from the Controller at the Sector.