Hi everyone, my brother had signed the Letter of Offer from a bank (Bank A) for housing loan but he haven't sign the loan agreement yet as they are still preparing the documents. He is refinancing his house loan with different bank btw.

He also submitted request of interest rate reduction to the bank (Bank B) that loaning him housing loan. Recently, Bank B called him up to offer him lower interest rate, just a bit lower than Bank A.

So, can my brother cancel Bank A's offer and continue with Bank B? What are the consequences? Please help! Thanks!