Repaint the parts with the colors 5 and 6 using the colors 3 and 4 in the Paint tool (use fill tool). Then remove 2 colors and reassign the colors 3 and 4 to the wished ones.
Unfortunately that is one of the short comings of the P series over the X/A series. You can’t re assign AMS filament selection from the printer. You have to do it via the App or from Bambu Studio.