This informs the tenant he or she hasn't paid rent, indicates the amount owed, and states if the rent isn't paid, you will begin eviction proceedings. (greenresidential.com)
However, they can't refuse unless there is a good reason (for example, that they have already started eviction proceedings against you). (moneyadviceservice.org.uk)
Worst case scenario, do I need to give someone power of attorney in order to start eviction proceedings on my behalf? (biggerpockets.com)