Change it into indirect

Dear student, 
The answer to your question is as follows:

After some time, Birbal walked up to one of the kings and greeted him. The king exclaimed with surprise that how had he recognized the real king. Birbal replied that after he had observed the other three king, he had found them watching him very closely and trying to imitate his actions and manners. But when he looked at at him he could see a calm and relaxed demeanour that indicated the true stature of a king. The king was pleased and rewarded him. 

Regards
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