First check the sources and the Latest Changes (found in the right hand column) to make sure it really is a wrong individual. If it is just a different spelling, under Other Information add an alternate name.
If it really is wrong, click on the edit icon by the person as a child to remove the parents or go to the spouse's page and in the marriage box click on the edit icon to remove the spouse. Be sure to include your reasoning so other researchers can understand why the individual is not part of the family group and will come to the same conclusion.
Please be careful when deleting "a tree", "a branch", or "a person"! You're not the only one related to them. It can cause extreme damage to other people's work and relationships. Perhaps instead of "deleting a tree", you could simply remove the sources and edit don't apply to your David Smith.
I am "Moving" this 'Question' of yours, in the 'Group' being "How to Use FamilySearch Community", in this "Community.FamilySearch" Forum, to the 'Group' being "General Questions", in the Forum; so that, the members of that group can answer/assist you.
As, that group of "How to Use FamilySearch Community" is about HOW to USE the "Community.FamilySearch" Forum itself, not so much for general help/assistance.
Please explain what is wrong.
Then, we may be able to advise/help.
It all depends on the situation/circumstances.
My 4th great grandfather in "Family Tree" is the wrong individual. He has the right name - David Smith - but he is the wrong David Smith. "My" David Smith of Farmington, CT was a private in the Revolution. The "wrong" David Smith in the tree was a major from Waterbury, CT. How do I make the change?
Does YOUR "David SIMTH" ALREADY exist (ie. is recorded) in "Family Tree" of 'FamilySearch'?
Or, do you need to "Create" a record for him in "Family Tree" of 'FamilySearch'??
Either way ...
At the moment, leave the WRONG "David SMITH" in 'situ' - as is.
IF, YOUR "David SIMTH" does ALREADY exist in "Family Tree" of 'FamilySearch'; THEN, associate that individual/person as a Spouse to Your 4th. Great Grandmother (and, 'Yes', as another, an additional, Spouse - we will address/fix that later).
IF, YOUR "David SIMTH" DOES NOT already exist in "Family Tree" of 'FamilySearch'; THEN, "Create" Him and associate that newly created individual/person as a Spouse to Your 4th. Great Grandmother (and, 'Yes', as another, an additional, Spouse - we will address/fix that later).
That done ...
Through extensive research (ie. doing your 'due diligence'), make 100% certain that the 'so called' WRONG "David SMITH" is NOT, in fact, the RIGHT "David SMITH".
Once you have done your 'due diligence'; and, established that the WRONG "David SMITH" is NOT Your 4th. Great Grandfather; then, simply, "Remove" him from the "Couple" Relationship with Your 4th. Great Grandmother.
Now, Your 4th. Great Grandmother, should have the CORRECT Spouse associated; and, You should have the CORRECT 4th. Great Grandfather.
Here is a "Knowledge Article" in 'FamilySearch':
A person in Family Tree has the wrong spouse
I hope this helps.
Hello @Larry Turner ,
How are doing with that problem you had.
Did you figure it out?
I believe I have enough information on the process of making a correction. But I need to assemble my scattered documentation before creating a new David Smith.
I need to delete a tree and begin again due to errors. [email protected]
I'll be careful. I don't intend to delete a tree or a branch. But a wrong individual does not belong in my direct ancestry, regardless of how much work it took to put the wrong individual there. Someone took from a DAR-based source that is incorrect. Many descendants of (the correct) David Smith who do genealogy have known this for decades. The correct David Smith in my line was not a physician; he was not a major, not even a commissioned officer; he was not from Waterbury. And unlike Major Dr. David Smith, my (Pvt/Cpl) David Smith did not have a son who became the "Father of the Atlantic Liner" and had a biography written that clearly indicates Maj. Smith is not my ancestor, never lived in Farmington, and had children named far different than my ancestors, the children of the correct David Smith. Good research would have borne this out.