#include <bits/stdc++.h>
using namespace std;

#define SZ(a) (int)a.size()
#define ALL(a) a.begin(), a.end()
#define FOR(i, a, b) for (int i = (a); i<(b); ++i)
#define RFOR(i, b, a) for (int i = (b)-1; i>=(a); --i)
#define MP make_pair
#define PB push_back
#define F first
#define S second
#define FILL(a, b) memset(a, b, sizeof(a))

typedef long long LL;
typedef pair<int, int> PII;
typedef vector<int> VI;

const int N = 447;
int n, m;
string a[N];
set<PII> s;
queue<PII> q;
string str = "BW";

bool ok(int i, int j)
{
	if (i == n - 1 || j == m - 1) return false;
	if (a[i][j] == 'B' && a[i + 1][j] == 'W' && a[i][j + 1] == 'W' && a[i + 1][j + 1] == 'B') return true;
	if (a[i][j] == 'W' && a[i + 1][j] == 'B' && a[i][j + 1] == 'B' && a[i + 1][j + 1] == 'W') return true;
	return false;
}

void check(int i, int j)
{
	if (i == n - 1 || j == m - 1 || i < 0 || j < 0) return;
	vector<PII> v;
	FOR(ii, i, i + 2) FOR(jj, j, j + 2) if (a[ii][jj] == '?') v.PB({ii, jj});
	if (SZ(v) > 1 || SZ(v) == 0) return;
	FOR (t, 0, 2)
	{
		a[v[0].F][v[0].S] = str[t];
		if (ok(i, j))
		{
			a[v[0].F][v[0].S] = str[t ^ 1];
			s.erase({v[0].F, v[0].S});
			q.push({v[0].F, v[0].S});
			return;
		}
	}
	a[v[0].F][v[0].S] = '?';
}

void solve()
{
	cin >> n >> m;
	FOR (i, 0, n)
	{
		cin >> a[i];
		FOR (j, 0, m)
		{
			if (a[i][j] == '?') s.insert({i, j});
		}
	}
	FOR (i, 0, n - 1)
	{
		FOR (j, 0, m - 1)
			check(i, j);
	}
	while (true)
	{		
		while (!q.empty())
		{
			int x = q.front().F;
			int y = q.front().S;
			q.pop();
			
			FOR(i, -1, 1) FOR (j, -1, 1) check(x + i, y + j);
		}
		if(s.empty())
			break;
			
		int X = s.begin()->F;
		int Y = s.begin()->S;
		
		s.erase(s.begin());
		a[X][Y] = 'B';
		q.push(MP(X, Y));
	}
	bool ans = 1;
	FOR (i, 0, n)
	{
		FOR (j, 0, m)
		{
			if (a[i][j] == '?') ans = 0;
			if (ok(i, j)) ans = 0;
		}
	}
	s.clear();
	cout << (ans ? "YES\n" : "NO\n");
	if (ans)
		FOR (i, 0, n) cout << a[i] << '\n';
	
}



int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	int t;
	cin >> t;
	while (t--)
	{
		solve();
	}
	
	return 0;
}