Withdrawal of Certificate in form 15CB

What is the time limit for a CA to withdraw form 15CB issued to a client for remittance of funds outside India? One of my clients got his form 15CB issued from a CA in my contact 5 days ago as I did not have a digital signature that time. He wants to withdraw it now, but the CA is hospitalised, in ICU and cannot be contacted. Is there any adverse implication if 15CB is not withdrawn within specified time limit? Meanwhile, the client has already withdrawn form 15CA filed from his log in.