Tense

I already asked this question on a different forum. However, I am not satisfied with the answer and I still would love to hear what others might say.

Hello! I want to ask whether or not this sentence below is correct.

Hi, I wanted to say thank you for all the things you've done today.

I'm kind of confused with the usage of the word "wanted" here. Why is it in the past tense? Is this correct? Shouldn't it be "want"? Thanks in advance.