Before requesting and lock extension, first you need to determine whether the lock can be extended by the number of days you require. This check is done with the getEstimatedExpirationDate call. Provide the priceQuoteId of the locked price and the number of days by which you wish to extend the lock. The call will return whether or not your required extension is available for the given price quote.
/rest/v1/lp-ppe-api/getEstimatedExpirationDate/{priceQuoteId}/{days}
The {priceQuoteId} is the id of the quote you want to extend
The {days} parameter is the number of days by which you wish to extend the lock on the loan.
This call contains no body.
The call returns a boolean yes or no.