TIER2 ICT- Long Term ISC -COS : Change of Work End Date in COS post Visa Stamping

[KUNU1686]

Hi All,
Need suggestions on the below situation on Change of COS Work End Date by employer after stamping of UK Visa.

Cos Work Start Date : 15-APR-2019
Cos Work End Date : 20-APR-2020

COS EXPIRY DATE: 02-JULY-2019

I haven't yet traveled and there is a delay in travel, and my employer is looking Vignette transfer for Extending the stamping by another 30 days as the initial 30 days stamping is ending on 07-MAY-2019

I would like to ask the forum, considering the above details, will my employer be able to :

1) Change my COS WORK END DATE from 20-APR-2020 as mentioned above to a further future date??

IF NOT

Can my employer, cancel the current COS which is active 02-JUL-2019(considering 90 days of validity) and apply for a fresh new COS immediately or is there some cooling period before applying a fresh COS.??

Please do help me with reply.

Regards,
kunu1686