Use the ReplaceBlock command to replace all instances of a specified Block by another specified block. The command lets you to purge the definitions of the replaced blocks.
To replace block instances by another block:
Note: You can change or add BlockAttributes to an existing Block definition by redefining the Block using the MakeBlock command. You can also modify the definition and properties of BlockAttributes with the EditComponent command. Both commands update the geometry of all instances of the redefined Block, but they do not automatically update the BlockAttributes that have been modified.
Access
Command: ReplaceBlock
Menu: XtraTools > Block > Replace Block
Ribbon: XtraTools > Block > Replace Block