Eligibility and limits for people born in Scotland
NRS says you can use its formal service if you were born or adopted in Scotland, unless the change is due to marriage, divorce or civil partnership. Its published limits depend on age: under 16, one forename and one surname change; from 16, one forename and up to three surname changes, with at least five years between surname changes. National Records of Scotland: changing your name; National Records of Scotland: application and age limits
These are limits of the NRS record-changing service. Do not mistake them for a general claim that a person can never use another form of name evidence. If the register has already recorded its permitted change, ask the organisation requesting evidence which document it will accept for the later change.