task. h

void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority );

INCLUDE_vTaskPrioritySet must be defined as 1 for this function to be available. See the configuration section for more information.

Set the priority of any task.

A context switch will occur before the function returns if the priority being set is higher than the currently executing task.

Parameters

pxTask	Handle to the task for which the priority is being set. Passing a NULL handle results in the priority of the calling task being set.
uxNewPriority	The priority to which the task will be set.

Example usage:

 void vAFunction( void )
 {
 xTaskHandle xHandle;

Create a task, storing the handle.
     xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle );

...

Use the handle to raise the priority of the created task.
     vTaskPrioritySet( xHandle, tskIDLE_PRIORITY + 1 );

...

Use a NULL handle to raise our priority to the same value.
     vTaskPrioritySet( NULL, tskIDLE_PRIORITY + 1 );
 }