Not clear what you're asking for here but a review of the number of councillors for parish councils is usually the remit of a review of the principal authority but in accordance with strict procedural guidelines. When a boundary review is carried out, the review of the number of councillors for affected parishes usually takes place at the same time but I believe you can ask for a review. I'm not sure of the procedures and believe it can take a long time to undertake but suggest you ask your principal authority.