Legal Question in Real Estate Law in California

Possibly, but more often than not, this would be an impermissible enlargement of the scope of the easement. First, it would be better to negotiate a new easement agreement including the neighbor needing the easement than to trigger litigation by enlarging the use of the easement in probable violation of its permissible use. I think the starting point is a careful review of the language of the existing easement, to see how tightly its permissible use is defined (or implied). Most easements can have mildly expanded use over time without creating a over-use violation, as courts have held that the original writers could have foreseen (for example) that cars would get bigger and faster, or that families would grow and make more trips over the roadway. However, cutting in a third-party user is probably going to be an overburden in the eyes of a court.....but all the facts and circumstances should be reviewed with a lawyer with some easement experience. Another factor could be WHY the neighbor doesn't have access to his property and thus needs the easement..... there are separate rules for "easements by necessity" which should be brought up in any discussion with a lawyer.