You want to have a committee with PTO parents that are familiar with the workings of the PTO, but not perceived as a "click". Have only one or two members of your Executive Board as part of the group since they will be able to offer advice of the interworkings of the PTO and what will or won't be feasible to carry out.
Once the group has their proposed changes, they are to be presented at a PTO meeting. We had the old wording and then the new wording so parents could easily see the changes that were being proposed. If we had something brand new, we stated it as such.
Vote on each item; one by one and 2/3 must vote in favor to carry it through.
We announced our voting on the new bylaws items to the entire school so any parents that wanted to be there to vote (make sure they are eligible to vote) could make the effort.
It went very well and they felt they were very well informed having the old and new wording. They were comfortable with the proposed changes.
Do your bylaws dictate how they can be amended? Our bylaws contain the following. Hope it helps
Article XV - Amendments
These bylaws may be amended at any regular or special meeting, providing that previous notice was given at the prior meeting in writing and then sent to all members of the organization by the secretary. Notice may be given by postal mail, email, or fax. Amendments will be approved by a two-thirds vote of those present, assuming a quorum.