We really cant tell with this lack of information. You might ask some locals who have lived in the area for a longtime if the swans are wild or captive. If the swan is captive, it will go about its business without a new mate especially if it is a male. If it is wild it will fly and find itself a mate if it chooses. No intervention is needed as their are no guarantees that it will accept a new swan on the pond. To introduce a new captive swan will mean that a pen completely fenced from top to bottom will need to be constructed to house the new swan so that it can be protected from predators and introduced to the old swan to ensure no aggression.

Before all of this happens, the present swan needs to be captured and sexed to determine the gender of swan that can be introduced. You cannot introduce the same gendered swan in this case. Again there are no guarantees that this will work which is why we would suggest to do nothing. You may also need a permit to bring in another swan. The Regal Swan