Sanders gave Clary a check but left the amount incomplete. The check was given as advance payment on the purchase of 100 LT speakers. The amount was left blank because Clary had the right to substitute other LT speakers if they became available and the substitution would change the price. It was agreed that in no event would the purchase price exceed $5,000. Desperate for cash, Clary wrongfully substituted much more expensive LT speakers, thereby increasing the price to $5,700. Clary then negotiated the check to Lawrence, one of his suppliers. Clary filled in the $5,700 in Lawrence’s presence, showing him the shipping order and the invoice applicable to the sale to Sanders. Lawrence accepted the check in payment of $5,000 worth of overdue debts and $700 in cash. Can Lawrence recover the full amount? Why or why not?