You can change number – however the old/existing number has to be accessed at the time of change so that we can confirm with you that it is you who is trying to access /edit your personal details. In case you lose your phone or access to your existing number and cannot retrieve it, then you have to contact Rightmove. Please call us on 01908 712126 or email us at mortgagesfeedback@rightmove.co.uk.