When encountering the movement of equipment in production, I believe that a re-validation is a necessary step. However, as some have mentioned above, it must be identified if a full Validation process is required in order to utilize equipment. This is important because the company needs to ensure that the equipment is still able to produce the consistent product. In my experience, there was a time that a equipment had to be moved 1 foot within the cleanroom due to maintenance requirements and it was a subject that was debated for some time due to the re-validation that would need to occur. So there is not set circumstance that would apply to your need Fady since every situation can differ. Even though a re-validation is a time consuming process at times, it is put in place for maintaining the high quality of the manufactured product.