Most employment relationships are "at will", which means that a company can set the conditions of the workplace much as it sees fit. This includes changing job duties such as requiring an office worker to do manual labor. The only protection that you might have is if this action violates the terms of a union agreement/employment contract, or your treatment constitutes some form of legally actionable discrimination (neither of which you indicated to be the case). As this point, you can either comply and help with the move, complain but risk termination, or quit.