Dear Mr. Bingham,
If you want to lease to Tomahawk Petroleum, you might be able to do so. It depends on what your draft or order of payment actually says. There is a court case - Spellman v Lyons - that gives a way to cancel the transaction prior to the draft being paid.
If you want, level with Tomahawk and let them make a business decision. However, the lease form may rule the day. Make sure that you are properly represented in this particular situation. This could get sticky, very quickly.
Best,
Buddy Cotten