Neighbourhood Plan Designated body - Public forum - Planning Advisory Service (PAS)

One of our Neighbourhood Areas' designated bodies is a parish council who will be reducing in number (approximatly half) following a number of members not standing for re-election. The new members are likely to be a mix of elected members and co-opted members. I have been asked if this will have any impact on the Neighbourhood Plan and role of the designated body?  ​​​​​​​

Thanks for any thoughts and advice.