Detailed Drawings > Annotating the Drawing > Working with Symbols > Defining Symbols > About Defining Symbols
  
About Defining Symbols
On the Annotate tab, click the arrow next to Symbol, and click Symbol Gallery. The SYM GALLERY menu appears. Use the Redefine command 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.