Yes, supplication is from the means by which a person attains that which he supplicates for and in reality supplication repels the divine decree and at the same time it doesn’t, meaning that there are two to aspects to it.
For example, an ill person supplicates to Allaah, and then he is cured. Now, if he had not made the supplication he would have remained in his state of illness, but because of the supplication he was cured.
However, we say, verily, it was Allaah who had decreed for the ill person to be cured from his illness by way of the supplication. So this was something written previously (decreed).
So it appears that the supplication has repelled the decree, whereby a person thinks that if it wasn’t for the supplication he would have remained ill, however in reality the supplication does not repel the decree since the supplication was already written (decreed), as was the fact that the cure would occur by way of the supplication.