I may be wrong but I believe that an invitation to make a state visit to the UK is made to the office of President or Monarch, not to the person who occupies that office.
It would be seen in the US as a huge diplomatic snub to the office of President if the original invitation were to be withdrawn. The consequences could be very harmful to future relationships between our two nations and possibly damage the efforts of those who work together in searching for peaceful co-existence in other areas of the world.
Whatever we think of Donald Trump as a person, let us at least respect the office of President...........who knows, it may bring opportunities to clear the air on a personal basis and to find better ways to promote world peace.