To change the date and time of a post in most social media management tools, the general steps are usually as follows:

1. Login: Log in to your Posttely account and navigate to the dashboard or the section where you manage your scheduled posts.

2. Locate the Post: Find the post you want to reschedule. It might be in a queue, a list of scheduled posts, or a similar section.

3. Edit the Post: There should be an option to edit the post details. This could be an "Edit" button, a pencil icon, or something similar. Click or tap on that option.

4. Adjust Date and Time: In the editing interface, you should see the date and time details for the scheduled post. Modify these to your desired date and time.

5. Save Changes: After adjusting the date and time, make sure to save your changes. This might involve clicking a "Save" button or a similar action.

6. Confirmation: Check for any confirmation message or notification that confirms your changes have been saved.