We don't have the means to delete a specific post in a wall, however you can get rid of a post by using a custom post spacing on the wall in question.
If you wish to have a three bays at 8ft and one at 12 and the rest at 8, then you can enter 8,8,8,12,8 as the custom spacing. This can be done in Advanced edit at the top, then selecting the particular wall that needs to be edited.
Posts that sit at the corner of a wall can be removed by setting the corner post material to 'None' or by Assigning corner posts to form part of the Eave or Gable wall
