Energetically speaking, the fear energy turns into anger when it intensifies and projects, or when the apparent cause of the fear seems to be getting worse.
Being afraid means you see yourself as a victim and as attacked, which means you also see yourself as unfairly treated, which means you think you are justified in being angry because something's happening that you didn't ask for. So anger arises out of a perceived fearful situation.
Since the anger is based on the fear and doesn't really have its own foundation, and is made to DENY the fear, if you acknowledge that you're actually really afraid, it completely shuts off the generation of anger. It doesn't deny it or hide it, it simply disappears. What this means is you've moved up the ladder, or rewound the chain of cause and effect, to where you are now willing to 'stay with' the fear rather than build upon it. The anger will simply disappear when you admit to this.
So let's say something is happening to someone close to you and it scares the shit out of you. And maybe there doesn't seem to be anything you can do about it. And maybe you depend on that person and if that person has an issue, then .... who is going to look after you, or where are you going to get your ego needs met? So then you perceive that your own needs are going downhill as a result of the other person, which is frightening. And because you perceive that you depend on the other person to save you, and they can't even save themselves, you're going to get angry at them for failing to give you what your ego wants. This will make you snowball into a spiral of fear and anger, as you practically demand that the other person get out of their situation.
Secretly this is based on ego selfishness and your own dependent and fearful ego needs, which if unmet by the special relationship, sends you into a spiral of desperation. As soon as you can admit this and realize that YOU have a problem, YOU are afraid, YOU need help, this will dissolve the entire expression of desperation and demands, deflate all of the 'anger' completely, and put you in touch with what really needs to be healed ... your ego ego attachment and dependency and belief in your OWN inadequacy, which the other person is just triggering off to show you.
Once you admit to being afraid, you might have an emotional release, and this will actually shed a lot of light on the situation and show you that it is not as bad as you thought. The other person was probably being attacked by your dependency on them, and by your fear, and by your own neediness, and this was showing you a worse perception than was really called for. Things are not as bad as they seemed, once you do this. And then you can work with Holy Spirit on healing your OWN issues of desperation, whether they be fear of abandonment or rejection or 'who is going to love me' or 'how do I get my needs met be other people'.
There is a plan for salvation. Honestly is the vehicle, Holy Spirit is the destination.