Replacing blocks with other blocks
Use the Replace Block command to replace each occurrence of a block with a different block. Select the block to replace and the replacement block from a list of all blocks available in the current drawing, and then choose whether to purge the unused block definition from the drawing.
To replace a block
1 Do one of the following to choose Replace Block ():
On the ribbon, choose Express Tools > Replace Block (in Blocks).
On the menu, choose Express Tools > Blocks > Replace Block.
Type blockreplace and then press Enter.
2 In Select Original Block, select the block that you want to replace. Or click Pick to select the block directly in the drawing.
3 In Select Replacement Block, select the block that you want to use as a replacement block. Or click Pick to select it directly in the drawing.
4 Click OK.
5 To remove the unreferenced block definition from the drawing, choose Yes. To keep the block definition in the drawing, choose No.