There is a difference between the sin against the Holy Ghost and lying to the Holy Ghost. The former has no forgiveness Mat 12:31, but the latter is also very serious.
Peter mentions it in Acts 5:3,9 and solemn consequences followed.
When ministers take ordination vows they are making promises to the Lord as well as to men. If they do this with mental reservation, one could argue that they are lying to the Holy Ghost.
It has become common for those who have taken ordination vows, when their mind changes to try to change the ordination vows of the whole church. The tail wags the dog.
The argument commonly put against this is that the Church must have a method of constantly reforming. This is true, but ordination vows and creedal subscription is the Scriptural method of ensuring that faithful men are at the helm 2Tim 2:2 – men whose word can be trusted and who can be trusted to do the reforming. They ought not to prevent reformation of the Christian Church towards more conformity to Scripture.
When people find that they can no longer fulfil their ordination vows, the honourable thing is to say so and to resign rather than to force the issue so that other people must resign.