Yes, you can accept an invitation if you have declined for a good reason and your plans changed. You should phone the hostess; host or bride if it's a wedding.
A homograph for "deny" is "denied" as in "they denied the allegations." A homograph for "decline" is "declined" as in "she declined the invitation."
When sending a wedding invitation the response card should go into the response envelope and you should address it back to you on the front of the response envelope with a stamp on the envelope.
Samantha, an introvert by nature, preferred her own company and declined the party invitation.
You can respond if there is an RSVP. The invitation or email invitation should direct you how to respond. Phone, email or letter may all be appropriate.
Nevertheless,Judy strongly declined the offer to go fishing with jack;she's fallen out with him due to his lack of interest in her!
I sold my stock when the market showed a sudden decline.
Thomas Paine declined the invitation to attend the Constitutional Convention. He did not believe in a strong central government that the new Constitution would enact.
Declined invitationsThe Beatles/John LennonThe DoorsLed ZeppelinJethro TullThe ByrdsTommy James and the ShondellsBob DylanThe Moody BluesSpiritJoni MitchellSimon & GarfunkelThe Jeff Beck Group
a solicited proposal is one which is prepared in response to specific invitation or demand
Yes, there is nothing wrong with that.
It seems like there was a typographical error: perhaps you meant to say "declined." To decline typically means to refuse or reject something, such as an offer or invitation.