(b) Subject to subsection (c), an anatomical gift by a person authorized in section 9 may be amended or revoked orally or in a record by any member of a prior class who is or becomes reasonably available after the execution of the document of gift. If more than 1 member of the prior class is or becomes reasonably available after the document of gift was executed, the gift made by an individual authorized under section 9 may be:

1. (1) amended only if a majority of the reasonably available members agree to amend of the gift; or
2. (2) revoked if a majority of the reasonably available members agree to the revoking of the gift or if the available members are equally divided as to whether to revoke the gift.