In the Position View screen press the track wheel and select Limit Order function from the side menu.
In the Limit Order screen, scroll down to the very bottom field and enter the necessary Limit rate changes.(In this case your Limit price must be higher than 1.5172)
* Note: Since you are changing the Limit Order Rate, you now are given more options in the Limit Order screen side menu.

Once required field is filled in, press the track wheel and choose OK function from the side menu
When confirmed you will be redirected to the Position View screen for the position you have just worked with
Scroll down to the Limit field where you should be able to see the new Limit Order Rate you have just changed for this particular position