I have negotiated such rates before for myself and my project teams.
First I find the lowest rate in the system, weekend, govt, AAA whichever provides the lowest reference point. If airline crews stay there regularily those rates are normally very good as well.
Second I contact the Sales Manager at the hotel and request the targeted rate based upon staying 30 nights etc in their hotel.
Third, so that it is clear, I let them know that I will check in and out to prevent the dreaded 30 day rule from kicking in.
Fourth and the Sales manager will know the local laws best, for some extended stays there are special tax advantages. I.E. VAT Exempt, since basically your leasing an apartment, but this can be very complicated and they will probably know the rules. This can be a HUGE pricing advantage if worked right.
I have handled the discussions by Phone, email and in person. Phone works the best for me.
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AA member since 1981. Oracle Implementations .... Will Travel....