#include <bits/stdc++.h>

using namespace std;

const int N = 110;
int n, m; char S[N][N];
int A[N][N];

queue<pair<int, int>> Q;
inline void check(int x, int y) {
	if(x <= 0 || y <= 0 || x >= n || y >= m) return;
	int siz = A[x][y] + A[x + 1][y + 1] + A[x + 1][y] + A[x][y + 1];
	if(abs(siz) == 3) {
		if(A[x][y] == 0) A[x][y] = -A[x + 1][y + 1], check(x - 1, y - 1);
		else if(A[x + 1][y] == 0) A[x + 1][y] = -A[x][y], check(x + 1, y - 1);
		else if(A[x][y + 1] == 0) A[x][y + 1] = -A[x][y], check(x - 1, y + 1);
		else A[x + 1][y + 1] = -A[x][y], check(x + 1, y + 1);
	}
}

inline void solve() {
	cin >> n >> m;
	for(int i = 1; i <= n; i ++)
		cin >> (S[i] + 1);
	for(int i = 1; i <= n; i ++)
		for(int j = 1; j <= m; j ++)
			A[i][j] = (S[i][j] == '?' ? 0 : (S[i][j] == 'W') ? 1 : -1);
	for(int i = 1; i <= n; i ++)
		for(int j = 2; j <= m; j += 2)  A[i][j] = -A[i][j];
	for(int i = 2; i <= n; i += 2)
		for(int j = 1; j <= m; j ++) A[i][j] = -A[i][j];

	for(int i = 1; i < n; i ++)
		for(int j = 1; j < m; j ++)
			check(i, j);
	for(int i = 1; i <= n; i ++) for(int j = 1; j <= m; j ++)
		if(!A[i][j]) A[i][j] = 1, check(i, j), check(i - 1, j - 1), check(i - 1, j), check(i, j - 1);

	bool flag = true;
	for(int i = 1; i < n && flag; i ++)
		for(int j = 1; j < m && flag; j ++) {
			if(abs(A[i][j] + A[i + 1][j + 1] + A[i][j + 1] + A[i + 1][j]) == 4) flag = false; 
		}
	if(flag) {
		cout << "YES" << '\n';
		for(int i = 1; i <= n; i ++)
			for(int j = 2; j <= m; j += 2)  A[i][j] = -A[i][j];
		for(int i = 2; i <= n; i += 2)
			for(int j = 1; j <= m; j ++) A[i][j] = -A[i][j];
		for(int i = 1; i <= n; i ++) {
			for(int j = 1; j <= m; j ++)
				cout << (A[i][j] == 1 ? 'W' : 'B');
			cout << '\n';
		}
	} else cout << "NO" << '\n';
}

int main() {
	ios::sync_with_stdio(false), cin.tie(0);

	int T; cin >> T;
	while(T --) solve();

	return 0;
}