An Apprentice may change their Employer at any time and as long as the new employer can continue the Apprenticeship you would record this in the ILR as per the following:
From the ILR Provider Support Manual 6.4.5 Funding model 36: recording changes
Apprentice changes employer during the apprenticeship
619. If there is a change to the apprentice’s employer during their programme, then you must record a new Learner Employment Status record to reflect this.
620. A new Apprenticeship contract type FAM record must be added if the new employer has a different apprenticeship contract type to the previous employer, for example if the apprentice has changes from a levy paying employer to a non-levy paying employer then a new FAM record with ACT2 must be recorded. There should be no changes made to the learning aims.
621. You must record a new price record on the programme aim; this price must reflect the cost of the remaining amount of the programme to be delivered with the new employer. This residual cost must be recording using AFinCode = 3 for training and AFinCode = 4 for assessment, as applicable.
622. If an apprentice is made redundant, you must record this in a new Learner Employment Status record with Employment status code 11 or 12, as applicable. While the apprentice is eligible to continue their programme (see the apprenticeship funding rules), an Apprenticeship contract type FAM of ACT2 must be recorded: if the FAM code is not already ACT2 then a new record must be added.
623. If an apprentice becomes unemployed and is not eligible to continue their programme, they must be withdrawn from the apprenticeship.