I have a member of staff who has made a request for flexible working. They would like to work their full time hours of 35 per week but condense them into 4 days rather then 5. I am happy to agree to this request but what do I do about holidays etc.

For instance should holidays be pro rata’d to a 4 day working week or are they still full time entitlement because they are working full time hours?
Kathryn