You can easily add “am” to the end of the word and say “mam’noonam”, which sounds a little bit ladylike, but the usage is same.
You can also say “sepas”, which is the short form, but still formal.
You can easily remove “am” (which means “I am”) and say “moteshaker”.
You can also remove “am” (meaning “I am”) and say “mochaker”, but this is a very friendly word. “Mochaker dadash” is the equivalent of “thanks bro”.
You can easily remove “d” د from the end of the phrase to make it more friendly. (lotf dari لطف داری)
You may want to express deep thankfulness by adding “faravan” (færavan) at the end of the phrase. The full pronunciation is “ba tashakor-e(ə) faravan”, written as با تشکر فراوان in the Persian alphabet.