When your senior thanks you, you can respond in a gracious and polite manner. Here are some appropriate ways to reply:
"You're welcome! It was my pleasure to help."
"No problem at all! I'm glad I could assist."
"You're most welcome. If you need anything else, don't hesitate to ask."
"You're very welcome. I'm here to support the team."
"It was nothing. I'm always happy to contribute."
"You're welcome. I appreciate the opportunity to be part of the team."
"No need to thank me. We're all working together for a common goal."
"I'm glad I could be of help. Let me know if there's anything else I can do."
"You're welcome. Your guidance and mentorship have been valuable to me."
"Anytime! Thank you for trusting me with the task."
Remember to say it with a smile and a friendly tone to convey your sincerity and appreciation for their acknowledgment. Being gracious in your response helps foster a positive and supportive work environment.