Angels who commit egregious wrongdoing while on the earth often face severe consequences because of their betrayal. For blasphemy, the consequence is death. However, Angels rarely commit blasphemy unless they are being deliberately rebellious against God. When that is true, it usually is a sign that the Angel has been irreversibly contaminated by Satan. The solution is for the Angel to either surrender his spirit or join Satan.
Some Angels who have committed blasphemy have chosen to align with Satan because they believe that returning to heaven is no longer an option that is available to them. They know that the sins they have committed are unforgivable. God can forgive the sins committed against the physical person, but only the spirit of the person and the Holy Spirit of God can forgive the sins committed against the spirit.
If the Holy Spirit forgives one person of the sin of blasphemy, each person who has committed blasphemy of the Spirit is automatically forgiven. Similarly, if the Holy Spirit forgives an Angel of the sin of blasphemy, each Angel who has committed blasphemy is automatically forgiven. From that moment forward, the sin again becomes punishable by death.
When an Angel decides that he prefers to enter Satan's service in lieu of surrendering his spirit, he must relinquish all of the ties to heaven and to his Godly mission in the earth. He can continue to live on earth for his normal lifespan, and must then make restitution prior to entering Satan's service. For restitution, he must ask Satan to release ten million children of God who have never committed blasphemy or sexual immorality. As soon as the release occurs, the decision to join Satan becomes irreversible, and the Angel dies shortly thereafter. Only one in every thousand Angels who have come to the earth have had to make this decision. Very few have chosen to join Satan.
If instead of aligning with Satan, the Angel chooses to relinquish his spirit, the spirit is then put to sleep and the Angel ceases to function. In the event that another Angel is forgiven of the sin of blasphemy, the blasphemy committed by the first Angel also automatically would be forgiven. In that case, the Angel's spirit would be awakened and the Angel would be restored to full function.