Updating Block or Symbol File from HDL

Hi,

Is there a way to update the pins on an existing symbol or update the I/O table in an existing block from a VHDL file?

Here's what I'm trying to do:

I have a top level block diagram with symbols and blocks. I used the blocks to generate the original skeleton for my VHDL files. Later I had to add and remove a few ports in my VHDL file. Now I would like to update the block in my block diagram using the VHDL file. Is this possible?

Is it possible to do this for symbols?

Thanks