Question
Sir,  I have a double yellow rose that has changed to a white rose ??  How can I make it go back to a yellow rose??
It is planted in a east facing bed and faily sheltered.

Answer
Roses have blood lines just like human beings and your rose has had a white rose in it's background. For unknown reasons, one part of a rose will revert to a different coloured flower. The whole rose will not revert it will just be a certain cane. I would ignore the white flower, simple cut it off and the next bloom will probably be a yellow like the rest.