Tier 2 COS start date changes

[kps16]

Hi,

I have been assigned a Tier 2 General COS with the work start date as 15th May 2016 and due to previous engagement, the COS was assigned to me on 24th June and applied for visa and had the entry clearance on 22nd Aug 2016. The employer has agreed for the delay in start date. So, Can the COS start date be changed to my agreed joining date (it could be in first week of September)?
The other queries are:
*) If the start date can be changed, will it be the same COS with the new start date or will it be a new COS?
*) In terms of validity of COS (As I understand, the validity is 5 years), which period will be considered? Old start date to 5 years period or new start date to 5 years period or My entry clearance to 5 years period?

[manci]

As your CoS has been "used", it cannot be changed.

However, your employer can assign a new CoS to you and you can then apply for leave to remain. Unless the job is a shortage occupation the fee to pay will be £1,328 .

[kps16]

Sure, thanks for the update. If I continue to go with the existing one, how the maximum validity can be calculated?

[manci]

Assuming you had a 5 year CoS you will have to sop work on 14 May 2021 and leave the UK by 13 June 2021.

You will be eligible for ILR on 22 August 2021 but to bridge the gap you'll need a new Cos and a visa extension.

[kps16]

Thanks. I am in a 3 year Cos ending by Apr 2019.Can that be extended for another 3 years or only 2 years?