If you can change your mind after hours of negotiation, then you started without knowing what you wanted—and you owe the other party a consulting fee for the vision mapping session.
Auctions are institutionalized, meant to sell a vast number of good to a vast number of people at publicly agreed prices in quick order. Usually these are for liquidation, fundraising, and government contracts. You are not overstocked nor damaged goods nor are you an overpriced trinket from a charity banquet—do not establish your price as if you were. Governments are the exception.
Pay the highest price you’re willing. Give people what they’re worth and don’t attempt less. If the other party does, walk away right away.
When you offer to join a team, set your ceiling at the outset and don’t go above it. If you say, “Four hours is all I can do that day,” and the person gives reasons why you should give five, they need help with vision and mission. Explain it, “You’ve got too much at stake and seem to be over-budget. I’m a four-hour guy, you need a five-hour guy, and you need to either talk to your accounting department to get a budget for the right guy or talk with your visioning team about a four-hour plan.”
The “Trump” negotiation tactic was well-demonstrated throughout his life, even his presidency: Make the opening offer “hugely” outrageous, then “come to your senses” and ask for what you wanted in the first place. That’s for dealing with parties who don’t know what they want. When people open with that outlandish offer, I go straight to “vision” mode.
The same applies against delphi method and managed conversation.
Many people ask my permission to cancel appointments. I tell them the same, “It’s not my choice. Just figure out your schedule, then call me.”
I once made an ethics-related suggestion to an itinerant speaker about his content. He gave his propaganda-couched excuse, adding, “…if that’s okay with you.” I answered, “It’s not my choice,” and made him own his. That speaker just stood speechless.
Never “negotiate”. Either host an auction, plan a strategy meeting, or act unilateral-friendly so you never pressure others.