About Defining Symbols
Click Annotate > Annotations > Define Symbol . The SYM DEFINITION menu appears on the Menu Manager. Click Redefine, under GET SYMBOL, click Name and select a symbol to add, move, delete, or change detail items composing a symbol.
You can modify a symbol by doing the following:
Create new entities composing a generic symbol.
Modify existing entities composing a generic symbol.
Change the attachment style.
Change group definition by adding or removing entities from groups, or deleting one or all groups.
Effect of Symbol Redefinition on Instances
When you redefine a symbol, it affects the display of all subsequent instances and all symbol instances that you have added to a drawing using the By Reference command.