Best Trade Solution

to amend a reimbursement undertaking, the issuing bank, reimbursing bank and the claiming bank must agree. now say after issuance of reimbursement undertaking the beneficiary wants to change the claiming bank since that bank is not his bank. whats would be the solution here?

if there is an amendment in the reimbursement undertaking, is there any limit within which the claiming bank must accept it or is it like the amendment of letter of credit?

i think it depends on the mutual understanding among the related parties.