When to allow a new COS after withdrawal of a former job offer

[Chuelife]

I am outside the UK and I currently got a job offer for which a COS was issued. Before I applied for visa, I got another job offer which I prefer to the former one. I discussed with the first employer to withdraw the job which they obliged.
1. Do I need to get a confirmation of COS withdrawal for the previous offer before I can allow the new employee to issue a COS.

2. If I don't need to get a confirmation of the COS withdrawal, how long do I have to wait before I allow the new employee go ahead with COS issuance.

[Frontier Mole]

If the first COS has been withdrawn you can apply immediately once you receive the new COS.
The system only allows one valid COS to be issued at anyone time, so if your preferred employer can enter your details and gain a COS then the withdrawal of the initial COS has been completed.

[Chuelife]

Thanks a lot. This piece of information is very helpful.