[GRASSLIST:1057] reclass pixel values

[Andrzej Wroblewski]

Hi !

Please help me to solve this problem:
How convert data (raster, vector, site) from wgs84 coordinate system to UTM.

How can I change pixel values in small area of biggest picture. Using reclass implenented in GRASS 4.3, change all pixel with this value.
For example:
this is a part of raster data (presented in pixel values):

2  2  2  2  2  3  3  4  3  2  3 
3  3  2  3  4  5  6  4  4  4  3 
4  4  5  5  5  5  5  5  4  4  3 
4  5  5  4  4  4  4  5  3  3  3
4  5  5  60 60 70 60 5  4  5  5 
4  5  6  60 60 70 70 5  5  5  5 
6  6  50 50 60 40  6 6  6  5  4 
3  4  4  5  5  4  3  3  3  3  4
5  5  5  4  3  3  4  5  5  3  3 
5  5  6  7  5  5  5  5  6  6  6
...
...
...
..
60 60 40 56 54 34 54 70 60 ..

Pixel value range is 1-255.

I want change pixel only form central part. Not changing rest.
60-->4
70-->5
40-->3
But if I use r.reclass, I change those values in whole picture.

Any idea ??