Tier 2 Applied for Change in Employment with different Sponsor but decided to remain with previous sponsor

Hi,

I am a Tier 2 General Migrant and I recently applied for a Tier 2 change of employment visa with a new sponsor which was accepted and a new BRP was issued. The start date on the new CoS is only 2 months from now. I am still working for my previous sponsor as per section 218 of Home Office guidance.

Due to a number of reasons I have decided not to go ahead with the change in employment and have informed my previous sponsor that I want to continue working for them which they’ve agreed to and have agreed to assign a new CoS and apply for a new Tier 2 General visa. I have confirmed that my role is not subject to RLMT.

Do my previous employer now need to apply for a new change in employment visa or an extension of my previous CoS?

Does my new sponsor have to withdraw the CoS that was issued before my previous sponsor apply for a new visa?

How do my new employer handle my previous CoS as because I can still work for them until the start date of the new CoS that was issued the Home Office has not been notified from their side that it is going to expire - do they have to withdraw the previous CoS before applying for a new visa?