There could be a couple or reasons why you might be experiencing a delay;
1. First, the status might be pending for security reasons. This may be a sign that someone is trying to use your identity to file a tax return. The return has been placed on hold to give you an opportunity to cancel it if it doesn't belong to you. This can take up to 72 hours, after which your return will then be forwarded to the IRS, or if applicable, rejected. If rejected, you can then correct the rejection issue and resubmit. Please see this FAQ for reference.
2. Secondly, there could be a delay if your return has various refundable credits, such as the Earned Income Credit.
Note: Both instances may be applicable. That is, you could have a hold for security reasons first. And additionally for verification of the refundable credits in your return. In this case, delays might extend beyond 72 hours.
Once a tax return has been filed it cannot be changed, canceled or retrieved
You will have to wait for the IRS to either Accept or Reject your filed federal tax return.
If the return is rejected you can make the necessary changes and e-file again.
If the return is accepted you will have to amend your original tax return. An amended return, Form 1040-X, can only be printed and mailed to the IRS if the original tax return was not e-filed. The IRS will take up to 20 weeks or longer to process an amended tax return.
Before starting to amend the tax return, wait for the tax refund to be received or the taxes due to be paid and processed by the IRS.
See this TurboTax support FAQ for amending a tax return - https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-change-correct-return-already-filed/L4VjJ9BA2_US_en_US?uid=ld1n99kr