信用，是价值运动的特殊形式。信用证，即购货方开户银行为保证在交易合同规定的范围内代付货款，向售货方开户银行签发的凭证。在签发信用证前，购货方应先半贷款提交开户银行，另立帐户保管。售货方接到其开户银行通知后，在信用证限额以内，可按合同规寂向购货方主动发货，并就地向争行结算收取货款。拟写信用证支付的有关函电，要不得根据业务的进展情况，适时地对信用下支付业务提出合理要求，以防发生因失误而造成的纠纷。
范文1:信用证展期、范文2:改证、范文3:催证、范文4:磋商推迟付款
范文1信用证展期
信用证展期
我们遗憾地告诉你方，直到今天我方才收到你方有关上述售货确认书的信用证。在所述确认书上清楚地规定有关信用证应不迟于8月底到达我处。虽然你方信用证到达的期限已过，但鉴于我们之间的长期友好关系，我们仍愿装运你方订货。然而，由于信用证迟到，我们不能按售货确认书所定间装运货物。因此，需将信用证展期如下：
（1）将装运期延期至10月底（2）将信用证有效期展至11月15日
请注意我们要求在9月30日之前收到信用证修改收。否则，我们无法如期装运货物。
期盼及早收到你方信用证修改通知书。
SPECIMEN：EXTENDING VALIDITY OF THE L/C
Dear Sirs:
RE:EXTENDING VALIDITY F THE L/C
We regret to say that we have not received your L/C related jto above mentioned sales Confirmation until today. It is stipulated clearly in the Sales Confirmation that the relevant L/C must reach to us not later than the end of Aug Alought the reaching time of the L/C is overdue,we would like still to ship your goods in view of long-standing friend relationship between us . However , we can not make
ship ment of your goods within the time stipulated in the Sales Conifrmatin owing to the delay of th L/C, Therefore, the /C needs to be extended as follows.
(1)l\time of shipment will be extended to the end of Oct
(2)Validity of the L/C will be extended to NOv15,
