In Elite Dangerous, changing a system's allegiance to a desired one, involves manipulating the Background Simulation (BGS) to make an aligned minor faction the controlling faction. This is a complex, long-term process that benefits from consistent effort and player coordination.

It may also help to be pledged or at least have a particular Superpower or Major Faction you feel more represented by. If you are still unsure of all the possibilities, check out my other guide, which introduces you to all the Supoerpowers and Major Factions:
https://cs2bus.com/sharedfiles/filedetails/?id=3489843602

• Identify a Target System
  
  • Choose a system with a minor faction who is aligned with your desired allegiance. Check the System Map or Status tab for factions with the allegiance's logo. (See above)
    
    
  • Target low-population systems (e.g., under 1 million) for easier influence shifts.
    
    
  • Avoid systems with high player activity or strong non-"desired allegiance" factions, as they may counter your efforts.
  
  
• Research the System’s Factions
  
  • In the System Status panel, note the controlling faction (owns the main station) and its allegiance (e.g., Federation, Independent, Alliance and Empire).
    
    
  • Identify the influence percentageof the minor faction, which is aligned to your desired allegiance choice. Your goal is to raise it above the controlling faction’s influence.
    
    
  • Check the faction’s government type (e.g., Patronage, Corporate) and state (e.g., Boom, Civil Unrest), as these affect mission availability and influence gains.
  
  
• Increase your chosen Faction’s Influence
  
  • Perform activities to boost that faction’s influence while avoiding actions that harm it:
    
    
    • Missions:
      Accept missions from faction’s which represent your allegiance choice at Mission Boards at their stations.
      
      
      • Trade/Cargo Missions:
        Deliver goods or source commodities for profit.
        
      • Passenger Missions:
        Transport passengers, especially during Boom states or at damaged stations.
        
      • Data Courier Missions:
        Low-risk, no cargo needed, ideal for stacking.
        
      • Combat Missions:
        Eliminate enemy ships or complete massacre missions in Conflict Zones.
      
      
    • Trade:
      Sell commodities at Empire faction stations for profit (e.g., gold, palladium).
      
      
    • Exploration Data:
      Sell cartographic data to Empire faction stations.
      
      
    • Bounty Hunting:
      Turn in bounties from wanted ships at Empire faction stations (use a Kill Warrant Scanner for max gains).
    
    
  • Avoid actions that hurt any faction which is aligned to the allegiance you are aiming to convert the system:
    
    • Failing their missions.
      
    • Selling goods on their stations’ black market.
      
    • Killing their ships in combat.
  
  
• Monitor Influence Changes
  
  • Influence updates daily during the BGS “tick” (~12:00 UTC, timing varies). Check the System Status panel for the faction’s influence percentage.
    
    
  • Aim to raise the faction’s influence to match or exceed the controlling faction’s (often >60% to trigger a conflict).
  
  
• Trigger and Win a Conflict
  
  • When the chosen faction’s influence nears or exceeds the controlling faction’s, a pending state (e.g., Civil War, War, Election) appears after the daily tick.
    
    
  • After 3–4 days, an active conflict begins. Conflict type depends on faction government types:
    
    • War/Civil War:
      Fight in Conflict Zones. Select the chosen faction’s side and destroy the enemies.
      
    • Election:
      Complete non-combat actions (missions, trade, exploration data) for the chosen faction.
    
    
  • Participate daily in conflict activities. Each day’s “victory” contributes to the outcome.
    
    
  • Conflicts last up to 7 days. The faction with the most daily victories wins control.
  
  
• Outcome
  
  • If the chosen faction wins, it becomes the controlling faction, and the system’s allegiance shifts to the desired one, reflected in the System Map and Galaxy Map.

• Coordinate with Others:
  Join player groups which align with the allegiance of your choice.(e.g., via https://inara.cz/ or Discord) to amplify efforts and counter opposition.
  
  
• Leverage System States:
  Factions in Boom gain more influence from trade/missions. Avoid Civil Unrest or Lockdown, which limit missions.
  
  
• Avoid Overloading:
  Excessive actions (e.g., mission stacking) may hit influence caps in high-population systems. Spread efforts over days.
  
  
• Counter Opposition:
  Monitor rival faction influence. Complete missions/combat to reduce it if it rises.
  
  
• Use Efficient Ships:
  
  • Courier missions: Fast ships like the Cobra MK 5.
    
  • Trade: Cargo-heavy ships like the Type-9 or Cutter..
    
  • Combat: Ships like the Vulture or Federal Corvette.

• Time-Intensive:
  Flipping a system can take weeks, especially in high-population systems or with player opposition.
  
  
• Opposing Players:
  Rival players may counter your efforts, creating a tug-of-war.
  
  
• Powerplay Influence:
  Systems controlled by Powerplay Powers (e.g., Zachary Hudson) may have extra resistance. (See above to see which power supports which allegiance)
  
  
• Retreat Risk:
  If the chosen faction’s influence drops below ~2.5%, it may retreat from the system, forcing a restart elsewhere.

• Powerplay vs. BGS:
  Flipping a system via BGS is separate from pledging to a Powerplay Power (e.g., Aisling Duval). You can support Powerplay while flipping systems to aid fortification/control.
  
  
• Rewards:
  Flipping a system offers no direct credits/items but supports roleplay, unlocks missions corresponding to the controlling allegiance, and aids Powerplay objectives.
  
  
• Tools:
  Use INARA[www.inara.cz] or EDSM[www.edsm.net] to track faction influence and system states in real-time.

Sidenote: I hope you are enjoying the few guides I have already posted. I have fun writing them and summarizing features in the game which aren't made clear up-front. I hope the guides help and as always, enjoy the game!