Creating family crests is a fun part of MyHeritage. From what I can tell, however, it seems that the only way to modify a family crest is to start all over and create a new crest from scratch. It would be good to be able to save a crest in a form that one could go back and change just a few things.
This is not a big deal, but it is yet another case in MyHeritage where one is unable to build on the results of prior work. Other such instances are the inability of MyHeritage to extract and use caption/title/description information within uploaded jpeg photos. Likewise it apparenlty is not possible to import a gedcom and photos from Family Tree Builder and have the result be an editable online tree with editable photos that have all the photo associations and tags maintained. Furthermore, text formatting in biographies and notes seems to get messed up when moving between MyHeritage online and FTB.
MyHeritage is a very nice way to get information into family trees, but one must be prepared to do prior work over and over again in certain key instances.