最重要的就是提供一个合适的理由给他们咯。
Dear Mr/MS..
It's our great pleasure to hear that you have the interest to visit our factory which we have expect for long. however I'm sorry to tell that due that our factory may will move to another place, it's not an appropriate time to prepare for your visit. But we hope to invite you to our factory when we finish the move and get everything in ready for your visit. Thank you for understand.
如果是你们压根就不想他们来的话那就去掉which we have expect for long以及But we hope to invite you to our factory when we finish the move and get everything in ready for your visit.。如果只是希望延期最好加上这些以表诚意。
it is our great honor to have you visiting our factory, yet it is sorry to tell you that due to the fact that + reason
it give us great pleasure knowing that you want to visit our factory, however, we are at the busiest season now, therefore our first line manager may not have time to show you around, so we suggest maybe ...
GO OUT SHABI WAIGUOREN