Changing mysql procedure's DEFINER

Hi all

I have tried to backup all the mysql database using the mysqldump command but it gets stuck on some PROCEDURES because the user currently doing the backup is not the user that is defined in the DEFINER.

I have tried to modify the DEFINER through UPDATE sql command on table MYSQL.PROC but it seems we don’t have access to it.

How can we proceed in order to have access to those PROCEDURES and back it up properly?