Renaldo Mendez was planning a huge grand opening for his restaurant when it opened in February 6 of next year.He contacts James Southerland, who is the booking agent for a band that Renaldo wants to play in the restaurant the day of the grand opening. The agent is on the road in his car and verbally agrees with Renaldo that the band will be there for the grand opening.The call was made on May 15 of the current year.When the morning of February 6^th rolls around, everything is ready for the grand opening, except, the band does not show up.When Renaldo calls the booking agent, he denies having the conversation with Renaldo.Things get heated and right before the booking agent hangs up, Renaldo threatens to sue him.Despite the lack of a band, the grand opening was a success.Renaldo is able to retrieve his phone records to verify his call to the booking agent on May 15^th of last year.

What is the legal concept(s) being discussed? (There may be more than one.)