If you are selling within the UK and wish to update your CE Marking to UKCA Marking, you can use this existing report.
If your product changes in the future and you wish to continue selling on the UK Market, you will need to have the product reassessed by an Approved Body, such as the BBA.
Such reports will not be accepted by the EU in support of CE marking and, unless a further agreement is reached, retesting will be necessary.