Resizing Multidimensional Arrays

I really like the new slice functions in Blitz, but how can I use them on multidimensional arrays.

A little example

Local ClearField:Int[10, 10]

For local tx=0 to 10
  For local ty=0 to 10
    print Clearfield[tx,ty]
  Next
Next

ClearField[10,..20] '<--- this doesn't work

How can it be done to resize my array ClearField?